65FR37607 Importation of Grapefruit, Lemons, and Oranges From Argentina, Part 1/8
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[Federal Register: June 15, 2000 (Volume 65, Number 116)]
[Rules and Regulations]
[Page 37607-37669]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15jn00-9]
[[Page 37607]]
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Part II
Department of Agriculture
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Animal and Plant Health Inspection Service
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7 CFR Parts 300 and 319
Importation of Grapefruit, Lemons, and Oranges From Argentina; Final
Rule
[[Page 37608]]
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DEPARTMENT OF AGRICULTURE
Animal and Plant Health Inspection Service
7 CFR Parts 300 and 319
[Docket No. 97-110-5]
RIN 0579-AA92
Importation of Grapefruit, Lemons, and Oranges From Argentina
AGENCY: Animal and Plant Health Inspection Service, USDA.
ACTION: Final rule.
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SUMMARY: We are amending the citrus fruit regulations by recognizing a
citrus-growing area within Argentina as being free from citrus canker.
Surveys conducted by Argentine plant health authorities in that area of
Argentina since 1992 have shown the area to be free from citrus canker,
and Argentine authorities are enforcing restrictions designed to
protect the area from the introduction of that disease. We are also
amending the fruits and vegetables regulations to allow the importation
of grapefruit, lemons, and oranges from the citrus canker-free area of
Argentina under conditions designed to prevent the introduction into
the United States of two other diseases of citrus, sweet orange scab
and citrus black spot, and other plant pests. These changes will allow
grapefruit, lemons, and oranges to be imported into the continental
United States from Argentina subject to certain conditions.
EFFECTIVE DATE: June 15, 2000. The incorporation by reference provided
for by this rule is approved by the Director of the Federal Register as
of June 15, 2000.
FOR FURTHER INFORMATION CONTACT: Mr. Wayne D. Burnett, Import
Specialist, Phytosanitary Issues Management Team, PPQ, APHIS, 4700
River Road Unit 140, Riverdale, MD 20737-1236; (301) 734-6799.
SUPPLEMENTARY INFORMATION:
Background
The regulations in ``Subpart--Fruits and Vegetables'' (7 CFR 319.56
through 319.56-8, referred to below as the fruits and vegetables
regulations) prohibit or restrict the importation of fruits and
vegetables into the United States from certain parts of the world to
prevent the introduction and dissemination of plant pests, including
fruit flies, that are new to or not widely distributed within the
United States.
The regulations in ``Subpart--Citrus Fruit'' (7 CFR 319.28,
referred to below as the citrus fruit regulations), restrict the
importation of the fruit and peel of all genera, species, and varieties
of the subfamilies Aurantioideae, Rutoideae, and Toddalioideae of the
family Rutaceae into the United States from specified countries in
order to prevent the introduction of citrus canker disease (Xanthomonas
campestris pv. citri (Hasse) Dye). The citrus fruit regulations also
restrict the importation of the fruit and peel of all species and
varieties of the genus Citrus into the United States from specified
countries, including Argentina, in order to prevent the introduction of
the citrus diseases sweet orange scab (Elsinoe australis Bitanc. and
Jenkins) and the B strain of citrus canker, which is referred to in the
citrus fruit regulations as ``Cancrosis B.''
On August 12, 1998, we published a proposed rule in the Federal
Register (63 FR 43117-43125, Docket No. 97-110-1) to amend the citrus
fruit regulations by recognizing a citrus-growing area within Argentina
as being free from citrus canker. In that document, we also proposed to
amend the fruits and vegetables regulations to allow the importation of
grapefruit, lemons, and oranges from the citrus canker-free area of
Argentina under conditions designed to prevent the introduction into
the United States of two other diseases of citrus, sweet orange scab
and citrus black spot, and other plant pests.
The proposed rule was followed by three notices regarding the
comment period and public hearings for the proposed rule. Specifically,
on October 16, 1998, we published in the Federal Register (63 FR 55559,
Docket No. 97-110-2) a notice advising the public that we were
extending the comment period for the proposed rule by 120 days and that
we had scheduled a public hearing in Thousand Oaks, CA, to give
interested persons the opportunity for the oral presentation of data,
views, and arguments regarding the proposed rule. On December 4, 1998,
we published in the Federal Register (63 FR 67011, Docket No. 97-110-3)
a notice advising the public that we had changed the date and location
of the public hearing in Thousand Oaks, CA. Finally, on January 13,
1999, we published in the Federal Register (64 FR 2151, Docket No. 97-
110-4) a notice advising the public that we had scheduled an additional
public hearing to be held in Orlando, FL.
With the extension granted in the October 16, 1998, notice, we
solicited comments for a total of 180 days ending on February 11, 1999.
We received 332 comments by that date, including 63 comments received
at the public hearings held in Orlando, FL, and Thousand Oaks, CA. The
comments were from foreign and domestic producers, handlers, packers,
and processors of citrus fruit; Members of the U.S. Congress and
elected representatives of State and local governments; State plant
protection officials and officials from Argentine's national plant
protection organization, the Servicio Nacional de Sanidad y Calidad
Agroalimentaria (SENASA); and representatives of the U.S. Citrus
Science Council (USCSC), a group formed specifically to respond to the
proposed rule.
Seventeen of the comments were letters requesting that we extend
the comment period for the proposed rule, and 3 comments simply stated
that any decision should be based on sound science. Two hundred and
fifty comments, 148 of which were form letters offering support for the
position of the USCSC, raised concerns or made suggestions regarding
the proposed rule. Those comments are addressed in detail later in this
document. The remaining 62 comments offered support for the proposed
rule as it was written. Those commenters who supported the proposed
rule noted the mutual benefits of trade, recognized the scientific
basis of the proposed rule, stated that Argentine imports would provide
competition for citrus imports from other countries, saw an opportunity
to increase citrus exports to Argentina, noted that Argentine citrus
has been exported to markets in other countries--including citrus-
producing countries--without incident, and noted the positive economic
effects that Argentine citrus imports would have on consumers,
wholesalers, distributors, and ports of entry.
The comments that we received in opposition to the proposed rule
focused largely on the scientific basis and support for the proposed
mitigation measures and on the execution and conclusions of the risk
assessment that was used by the Animal and Plant Health Inspection
Service (APHIS) in reaching the decision to initiate the proposed rule.
These comments, as well as the numerous comments that we received on
other particular aspects of the proposed rule and its supporting
documentation, are reported and addressed in this final rule.
With regard to the proposed mitigation measures, several commenters
questioned whether the systems approach to phytosanitary security
explained in the proposed rule would provide an adequate measure of
protection against the introduction of the diseases and insect pests of
concern, especially given their understanding that APHIS had never
before used a
[[Page 37609]]
systems approach to mitigate the risks presented by a pest complex that
included both insects and pathogens. Other commenters questioned the
volume, adequacy, and accuracy of the scientific data provided by
Argentina to support the efficacy of the proposed mitigation measures
contained in the systems approach. As we discuss in detail below in
response to specific comments, we believe that the information
furnished by Argentina, when considered in conjunction with the body of
information available in the scientific literature regarding the
insects and diseases of concern, provides the necessary rational basis
for our determination that individual and cumulative mitigative effects
of the systems approach serve to reduce the risks presented by
Argentine grapefruit, lemons, and oranges produced and imported in
accordance with this rule to a negligible level.
With regard to the pest risk assessment prepared by APHIS, several
commenters disagreed with the manner in which we prepared the risk
assessment, questioning basic choices made by the risk assessors
concerning issues such as independence in the model and our use of a
shipping box as the risk unit. Other commenters questioned whether
APHIS offered sufficient justification for the estimates used in
section II.8 (Likelihood of Introduction) of the risk assessment. In
this final rule, we discuss, in our responses to specific comments on
these and other related issues, the manner in which we prepared the
risk assessment and how we arrived at our estimates. Our experience in
examining the risks presented by agricultural commodities produced
around the world has led us to select the model that we used as the
framework for estimating those risks. This model has proven itself over
the years and for several commodity/pest combinations to be an
efficient means of estimating phytosanitary risk, and we (and others,
including the Harvard Center for Risk Analysis) believe our guidelines
are valid. While we acknowledge that there are alternative ways of
estimating this type of risk, we do not believe that using a different
model would result in a substantively different outcome.
Distribution Limitations
In the proposed rule, we discussed the importation of grapefruit,
lemons, and oranges into the entire United States. However, the risk
assessment that was prepared prior to the preparation of the proposed
rule only examined the risks presented by the importation of that fruit
into the continental United States (the 48 contiguous States, Alaska,
and the District of Columbia). Although we have no reason to believe
that the risk associated with importing Argentine citrus into Hawaii,
Guam, the Northern Mariana Islands, Puerto Rico, or the U.S. Virgin
Islands would differ in any significant way from the risks associated
with the importation of that fruit into the continental United States,
the fact remains that the risk assessment did not consider the risks
associated with the importation of Argentine citrus into destinations
outside the continental United States. Therefore, in this final rule we
have narrowed the area into which the grapefruit, lemons, and oranges
may be imported by limiting the distribution of the fruit to the
continental United States. If we were requested to do so by Argentina
or other interested parties, we would undertake to assess the risks
associated with the entry of Argentine citrus into areas outside the
continental United States and initiate rulemaking to provide for the
entry of the fruit into those additional areas if our risk assessment
supported such an action.
We continue to have confidence in the efficacy of the systems
approach for Argentine citrus and in the conclusions of our pest risk
assessment, which found that the risk presented by grapefruit, lemons,
and oranges imported in accordance with that systems approach is
negligible. However, in response to comments from the domestic citrus
industry and others voicing concern over the use of a systems approach
in a situation where both diseases and insect pests exist in a foreign
production area, we will institute a limited distribution plan that
will delay the entry of Argentine citrus into citrus-producing areas in
the continental United States until 2004. This delay will provide an
opportunity for the efficacy of the systems approach to be demonstrated
under actual production and distribution conditions before Argentine
citrus imports are allowed to enter citrus-producing areas of the
continental United States. The limited distribution plan would involve
a three-stage phase-in of Argentine citrus imports:
<bullet> Stage 1 (the 2000 and 2001 shipping seasons). Upon the
effective date of this final rule, fruit that meets the requirements of
the export program will be eligible for entry into 34 States in the
continental United States that are neither buffer States nor commercial
citrus-producing States.
<bullet> Stage 2 (the 2002 and 2003 shipping seasons). When
Argentina begins shipping fruit in May or June of 2002, the fruit will
be eligible for entry into the 34 ``Stage 1'' States as well as the 10
buffer States (Alabama, Arkansas, Colorado, Georgia, Mississippi,
Nevada, New Mexico, Oklahoma, Oregon, and Utah) that share borders with
one or more commercial citrus-producing States, leaving only 5
commercial citrus-producing States (Arizona, California, Florida,
Louisiana, and Texas) as prohibited destinations in the continental
United States.
<bullet> Stage 3 (the 2004 shipping season). When Argentina begins
shipping fruit in May or June of 2004, the fruit will be eligible for
entry into all areas of the continental United States.
These ``rolling effective dates'' are built into the final rule,
which precludes the need for APHIS to initiate rulemaking in 2002 and
2004 to expand the area into which the fruit may be imported. If it is
determined that the requirements of the export program are not being
observed routinely or uniformly, APHIS will be able to act quickly to
suspend the rolling effective dates or even the entire program, if
warranted. The export program provides for the detection of diseased
fruit at any point in the pathway, with that detection leading to the
rejection of the shipment containing the diseased fruit and the removal
of the grove that produced the fruit from the export program for the
remainder of the shipping season. Thus, the detection of diseased fruit
will not, by itself, result in the suspension of all or part of the
export program.
To determine whether the requirements of the export program are
being observed routinely or uniformly and to ensure that the
distribution restrictions of this rule are being observed, APHIS
personnel will be involved in monitoring activities in both the United
States and Argentina:
Monitoring--United States. To help ensure that importers and
distributors of Argentine citrus are aware of the distribution
limitations of this rule, those limitations will be included as one of
the conditions of the permit that importers must obtain in order to
import grapefruit, lemons, or oranges from Argentina. APHIS personnel,
as well as personnel with State regulatory agencies and the
Department's Agricultural Marketing Service, will be enlisted to
enforce the distribution limitations of the rule. This will be
accomplished through market visits, inspections, and outreach efforts
directed at importers, shippers, distributors, and retailers. The
infrastructure needed to support these efforts is already in place.
Monitoring Argentina. The rule does not require direct APHIS
involvement in
[[Page 37610]]
the supervision of the export program in Argentina; that direct
supervision is the responsibility of SENASA, Argentina's national plant
protection organization, which is regarded by APHIS (and
internationally) as an efficient and capable organization. A recent
(April 24 to 28, 2000) site visit to citrus groves and packinghouses in
Argentina by APHIS bears out this perception. In order to evaluate
whether it is appropriate to allow each stage of the phased-in
distribution plan to occur as scheduled, and to provide for the ongoing
evaluation of the export program, APHIS will be conducting inspection
visits to the Argentine production area and will maintain contact with
SENASA throughout each year to monitor their administration of the
export program. Further, APHIS and SENASA are currently finalizing the
details of the annual operational work plan that will address the
administration of the program during the current season and that will
serve as the basis for future annual work plans. That work plan will
include provisions for active and direct monitoring of the export
program by APHIS personnel who will conduct frequent oversight visits
to the growing areas and packinghouses. APHIS' monitoring activities
will include:
<bullet> Inspections of groves following the removal of leaves and
other litter,
<bullet> Review of the timing and application of fungicidal sprays,
<bullet> Accompanying SENASA inspectors as they conduct preharvest
grove inspections and collect samples of fruit for laboratory
examination,
<bullet> Visits to the SENASA-approved laboratories that will be
examining the sampled fruit to review the procedures for, and results
of, the fruit incubation protocol,
<bullet> Observing the harvesting of fruit, its transport to the
packinghouses, and the entry control systems in place at the
packinghouses, and
<bullet> Ensuring that the required handling, treatment,
inspection, identification, and packing requirements of this rule are
being observed in the packinghouses.
These monitoring activities carried out by APHIS and SENASA
personnel will provide us with a clear confirmation of the
practicability of the systems approach under actual production
conditions, its efficacy in preventing disease in export groves, and
the ability of the required inspections and laboratory examinations to
detect diseased fruit. Additional evidence of the success or failure of
the export program will be gained through the inspections that will be
conducted at U.S. ports of entry following the arrival of the fruit and
the application of any required cold treatments. Should APHIS, as a
result of these activities or any other assessments of the program,
conclude that the requirements of the export program are not being
observed uniformly and routinely, the program will be reviewed; should
APHIS determine that there are deficiencies in the program that cannot
be remedied, the phased-in expansion of distribution, or even the
export program itself, may then be suspended or terminated.
Specific Regulatory Changes Regarding Limited Distribution
To implement the limited distribution plan, we have made several
changes to this final rule. These changes are explained below and
pertain to the distribution limitations themselves, box marking,
stickering, and ports of entry.
Limitations on Distribution.
We have added a new Sec. 319.56-2f(g) to this final rule to
incorporate the distribution limitations into the requirements of the
rule. That paragraph states that the distribution of the grapefruit,
lemons, and oranges is limited to the continental United States (the 48
contiguous States, Alaska, and the District of Columbia.). That
paragraph also states that during the 2000 through 2003 shipping
seasons, the distribution of the grapefruit, lemons, and oranges is
further limited as follows:
<bullet> During the 2000 and 2001 shipping seasons, the fruit may
be distributed in all areas of the continental United States except
Alabama, Arizona, Arkansas, California, Colorado, Florida, Georgia,
Louisiana, Mississippi, Nevada, New Mexico, Oklahoma, Oregon, Texas,
and Utah.
<bullet> During the 2002 and 2003 shipping seasons, the fruit may
be distributed in all areas of the continental United States except
Arizona, California, Florida, Louisiana, and Texas.
For the 2004 shipping season and beyond, the fruit may be
distributed in all areas of the continental United States.
Box Marking
As was presented in the proposed rule, Sec. 319.56-2f(c)(6) of this
final rule requires the boxes in which the fruit is packed to be marked
with the SENASA registration number of the grove that produced the
fruit. This final rule requires that the boxes also be marked with a
statement indicating that the fruit may not be distributed in Hawaii,
Guam, the Northern Mariana Islands, Puerto Rico the U.S. Virgin Islands
(i.e., destinations outside the continental United States), or in any
State (each of which must be individually listed) into which the
distribution of the fruit is prohibited under the limited distribution
plan. To account for the possibility that the fruit might have to be
repackaged following its entry into the United States, new paragraph
Sec. 319.56-2f(i) states that any new boxes in which the fruit is
packed must also be marked with the limited distribution statement
required under Sec. 319.56-2f(c)(6).
Stickering
APHIS has found that the marking of individual fruit is necessary
for the limited distribution scheme to be enforceable; otherwise it
would be difficult to distinguish Argentine grapefruit, lemons, or
oranges from domestically produced fruit or fruit imported from other
sources. Therefore, we have amended Sec. 319.56-2f(c)(5) in this final
rule to require that the grapefruit, lemons, and oranges be
individually labeled with a sticker that identifies the packinghouse in
which they were packed. We understand that Argentina's citrus producers
routinely label their fruit with stickers identifying the packinghouses
in which the fruit was prepared for distribution, and we believe that
those packinghouse labels would serve to adequately identify the fruit
since we would be able to provide examples of each packinghouse's
sticker to our inspectors and cooperators. Therefore, we do not believe
that this stickering requirement will impose a significant additional
burden on Argentine growers, packers, or exporters.
Ports of Entry
New Sec. 319.56-2f(h) states that the grapefruit, lemons, and
oranges may enter the United States only through a port of entry
located in a State where the distribution of the fruit is authorized
under Sec. 319.56-2f(g), which, as explained above, is the section of
the regulations that provides for the limitations on the distribution
of the fruit. The port-of-entry restrictions of Sec. 319.56-2f(h) apply
to both the limited distribution plan's staged phase-in of imports into
the continental United States and the prohibition on the distribution
of the fruit outside the continental United States.
As noted above, we believe that this limited distribution plan will
provide an opportunity for the efficacy of the systems approach to be
demonstrated under actual production and distribution conditions before
Argentine citrus imports are allowed to enter
[[Page 37611]]
citrus-producing areas of the continental United States.
Miscellaneous Comments
Comment: In 1995, APHIS denied Argentina's petition to export
citrus to the United States due to the risks that were posed by the
fruit. The proposed rule does not set forth the information and
experimentation that transpired between 1995 and 1996 that led APHIS to
reverse its position. It is only appropriate that the U.S. citrus
industry have the opportunity to evaluate the basis for APHIS' decision
to reverse its position.
Response: In our proposed rules, we usually focus on describing and
justifying the specific regulatory changes or additions that we are
proposing, so we do not routinely provide the sorts of historical or
evolutionary details that the commenter mentions. In the case of the
Argentine citrus proposed rule, we concentrated on explaining the
proposed citrus export program set forth in the regulatory text of the
proposed rule; we did not believe it was necessary to examine the
differences between that program and any earlier Argentine petitions
that we had rejected. However, the process of data gathering,
experimentation, and negotiation that led to the proposed rule is
documented in the material contained in the rulemaking record, and we
provided that material to several interested parties who requested it,
including representatives of the U.S. citrus industry.
Comment: Two documents in the rulemaking record--a trip report
prepared after APHIS' 1994 trip to northwestern Argentina and a
memorandum dated May 27, 1994, that discusses the status of Argentina's
request to export citrus both raise questions and concerns regarding
the Argentine petition. The May 1994 memorandum recommended two
actions: (1) That the Government of Argentina request a thorough risk
assessment be completed, and (2) that an expert group of pathologists
from APHIS and the Agricultural Research Service determine what
research was needed before a regulatory decision was made, establish
tolerances for diseased fruit in an export program and how these can be
measured, and make an assessment of Argentina's citrus canker survey.
While the call for a risk assessment in point number one may have been
addressed by APHIS' original 1995 risk assessment, the recommendations
on point number two appear to have gone unaddressed. We believe that
all those questions must be answered before APHIS takes any further
action on Argentina's petition. To that end, the proposed rule should
be withdrawn to allow for a full scientific discussion of the questions
found in those documents.
Response: Both of the actions recommended in the May 1994
memorandum were completed prior to the development of the proposed
rule. As noted by the commenter, APHIS did prepare a preliminary
qualitative pest risk assessment in 1995, and that 1995 assessment was
followed up by the 1997 quantitative pest risk assessment used as
support for the proposed rule.
In September 1994, our expert group of pathologists identified to
Argentina the areas in which we believed additional research was needed
and requested another year's worth of data to substantiate their
proposed mitigation measures; that data was received in the spring of
1996. Further, as evidenced by the provisions of the proposed rule and
this final rule, we established tolerances for diseased fruit in the
export program (i.e., the detection of a single diseased fruit will
result in the grove in which the fruit was grown being removed from the
export program, and the fruit from that grove being prohibited entry
into the United States, for the remainder of that year's growing and
harvest season). We have also included inspection provisions to detect
diseased fruit and prevent its entry into the United States. Finally,
we completed our review of Argentina's citrus canker survey program and
have full confidence in the efficacy of its methodology and the
accuracy of its findings. Given that all the issues raised in the May
1994 memorandum were addressed prior to the preparation of the proposed
rule, we do not believe it is necessary to withdraw the proposed rule
for the reasons stated by the commenter.
Comment: In 1994, Argentina proposed a systems approach to suppress
citrus black spot and sweet orange scab that was based on individual
farms performing the suppression treatment. At the time, APHIS stated
that individual farms were too small a unit for sufficient disease
suppression and that a larger area with clearly defined geographic
boundaries encompassing all citrus grown in the region would be
necessary. Why is APHIS now proposing a system based on individual
farms performing the suppression treatment?
Response: The original Argentine proposal did not include several
of the aspects of the systems approach required by this rule, such as
the preharvest surveys, laboratory analysis of sampled fruit, and post-
harvest treatments. When those aspects of the systems approach were
included in later proposals and data were made available to support
their efficacy, we concluded that a grove-level approach to the plant
pests of concern would be appropriate.
Comment: The 1994 trip report posits that one possible step that
could be taken in order to permit Argentine citrus to enter the United
States would be to limit exports to Northeastern ports. A limited
distribution requirement similar to the restrictions on the importation
of avocados from Mexico would not be a sufficient or enforceable
mitigation measure for Argentine citrus. If the market provides an
economic reason to ship the citrus to other States, parties with an
economic motivation to do so will find a way to make that happen. It is
not realistic to say that APHIS has sufficient resources to ``police''
this requirement. The result would be the spread of devastating
diseases to citrus growing regions. Indeed, APHIS has had recent
experience in dealing with illegal shipments of Mexican avocados by a
large retailer. Once Argentine citrus enters the United States, it must
be assumed that the fruit will reach every market in the continental
United States. Thus, any potential restriction on where the fruit can
be shipped is unrealistic.
Response: That suggestion was indeed offered during discussions
that preceded the preparation of the proposed rule, but the proposed
rule did not include limitations on distribution. This final rule does,
however, limit the importation of the fruit to the continental United
States and incorporates a three-stage phase-in of imports that limits
the distribution of the fruit during the 2000 through 2003 shipping
seasons. These aspects of this final rule are explained above under the
heading ``Distribution Limitations.'' As noted in that section, we
continue to have faith in the efficacy of the systems approach and in
the findings of the risk assessment, thus we continue to believe that
citrus fruit imported from Argentina in accordance with this rule
presents a negligible risk of introducing diseases or insect pests into
any area of the continental United States.
APHIS personnel, as well as personnel with State regulatory
agencies and the Department's Agricultural Marketing Service, will be
enlisted to enforce the distribution limitations of the rule. This will
be accomplished through market visits, inspections, and outreach
efforts directed at importers, shippers, distributors, and retailers,
and the infrastructure and resources needed to support these efforts
are already in place. Given the experience we have gained through the
Mexican avocado
[[Page 37612]]
program and through the implementation of our expanded smuggling
interdiction program, we believe that we have the ability to enforce
the distribution restrictions of this rule.
Comment: We requested a 1-year extension of the comment period for
the proposed rule, then shortened the requested length of the extension
to 6 months. By granting only a 4-month comment period extension and
subsequently denying our request for a 2-month postponement of the
scheduled public hearing, APHIS has denied the affected public a fair
opportunity to comment on the proposed rule.
Response: With the original 60-day comment period and the 120-day
extension noted by the commenter, the proposed rule was open for public
comment from August 12, 1998, through February 11, 1999, a total of 6
months. We believe that this 180-day comment period afforded the
affected public a fair opportunity to comment on the proposed rule.
Further, in denying the commenter's request for a 2-month postponement
of the California public hearing, which we had already postponed once,
the Department made it clear that it was willing to review any new
information that might surface following the close of the comment
period. Specifically, the APHIS hearing officer at the Thousand Oaks,
CA, hearing--which was attended by the commenter--read the following
statement from Deputy Secretary Richard Rominger: ``Following the close
of the comment period, we will thoroughly analyze and review the
available material and all comments in the record to determine how best
to proceed in the rulemaking process. However, if any new scientific
information comes to light after the close of the comment period on
February 11, 1999, which has a material and significant bearing on this
rulemaking proceeding, such information will be thoroughly considered
by the Department, and the Department will take such further action as
is appropriate.''
Comment: We informed APHIS on October 2, 1998, that our group was
organizing to comment on the proposed rule and had selected a
delegation of university scientists from California, Texas, and Florida
to travel to Argentina in order to gather information. By failing to
provide timely assistance to our group in arranging that trip, APHIS
has denied our group and other interested parties a meaningful
opportunity to conduct critical scientific analysis.
Response: We believe that the correspondence exchanged between
APHIS and the commenter concerning a site visit indicates that APHIS
cooperated with the commenter's group in its efforts to arrange a visit
to Argentina:
<bullet> After receiving the commenter's letter dated October 2,
1998, APHIS informed the Argentine Ministry of Agriculture of the
commenter's desire for a site visit by university scientists. Argentine
officials responded by requesting APHIS' endorsement of the visit prior
to granting their consent for a site visit.
<bullet> In a letter dated November 6, 1998, APHIS informed the
commenter of Argentina's response. In that letter, we stated that we
were prepared to endorse the visit and asked for a specific description
of its objectives so that we could pass that information along to
Argentina.
<bullet> In a letter dated December 1, 1998, the commenter
responded with the requested information and indicated its eagerness to
work with APHIS to arrange the trip.
<bullet> In a letter dated December 7, 1998, we informed the
commenter that we would endorse the visit and attempt to arrange a
visit in the second week of January 1999.
<bullet> In a letter dated December 17, 1998, the commenter
rejected the idea of a January visit, stating that the notice was too
short and that January was not a ``biologically relevant'' time for a
visit. In that letter, the commenter's group informed APHIS that it
wished to make a visit in April or May, and perhaps make another visit
in July or August.
<bullet> No further progress was made on the issue of a site visit
following that December 17, 1998, letter. In subsequent correspondence,
the commenter's group informed us that they would attempt to ensure
that the comment period was extended or the record otherwise held open
in order to provide for APHIS' consideration of any information
collected during possible future site visits by their scientists.
We believe that the timeline provided above shows that APHIS did in
fact provide timely assistance to the commenter, and we disagree with
the commenter's assertion that APHIS denied interested parties a
meaningful opportunity to conduct critical scientific analysis.
Comment: On September 22, 1998, we filed a Freedom of Information
Act (FOIA) request with APHIS in which we asked for any background
materials and correspondence relating to the 1997 risk assessment.
APHIS' FOIA office acknowledged that request on September 29, 1998, but
did not provide any material or acknowledge our follow-up request
before the end of the comment period. APHIS has, therefore, withheld or
failed to disclose relevant information that would allow the public to
interpret and understand the findings in the risk assessment.
Response: Due to our FOIA staff's large workload, we were unable to
fulfill the commenter's FOIA request before the February 11, 1999,
close of the comment period. However, we did forward the requested
documents to the commenter shortly after the close of the comment
period. As indicated in the response to a previous comment, we informed
the commenter prior to the close of the comment period that we are
willing to thoroughly consider, and address as appropriate, any new
scientific information that comes to light that has a material and
significant bearing on this rulemaking proceeding.
Comment: At the February 5, 1999, public hearing, a member of the
APHIS panel stated that APHIS was relying on a 1986 Plant Protection
and Quarantine (PPQ) study to support its position that it was highly
unlikely that citrus black spot would become established by the spores
produced on infected fruit. We believe that APHIS is using this PPQ
study as the pivotal foundation for the proposed rule. APHIS' failure
to disclose its reliance on this pivotal 1986 study until extremely
late in the proposed rule's comment period is a violation of proper
administrative procedures. APHIS has denied the affected public the
opportunity to comment on the Agency's rationale for the proposal; the
lack of disclosure of this one study, in and of itself, is a compelling
reason why this proposal must be withdrawn by APHIS.
Response: APHIS did not use the cited 1986 study as ``the pivotal
foundation for the proposed rule.'' Most of the APHIS employees
involved in the preparation of the proposed rule were either unaware of
or had forgotten the 1986 study. It was not until the panel that
represented APHIS at the two public hearings was preparing for the
February 5, 1999, hearing in Orlando, FL, that one of the panel members
recalled the existence of that study; this was more than 5 months after
the proposed rule was published. Further, the official transcript of
the February 5, 1999, hearing indicates that the APHIS panel member
simply quoted from the 1986 study; she did not state that APHIS was
``relying on'' the study. Because we did not rely on the study or its
findings in the preparation of the proposed rule, we do not believe the
fact that it was not mentioned until late in the comment period is
grounds for the withdrawal of the proposed rule.
[[Page 37613]]
Comment: APHIS did not comply with its obligations under Executive
Order 12866 in developing the proposed rule. In particular, section
6(a) of the Executive Order provides that each agency should engage the
impacted public with an opportunity for informal dialogue prior to
issuing a proposed rule. For this reason alone, APHIS should withdraw
the proposed rule to permit the required consultations to begin.
Response: The portion of the executive order cited by the commenter
reads in part: ``Each agency shall (consistent with its own rules,
regulations, or procedures) provide the public with meaningful
participation in the regulatory process. In particular, before issuing
a notice of proposed rulemaking, each agency should, where appropriate,
seek the involvement of those who are intended to benefit from and
those expected to be burdened by a regulation.'' Consistent with our
standard procedures, APHIS did in fact informally contact
representatives of the domestic citrus industry regarding the Argentine
proposal in October 1997, and indications at that time were that the
domestic citrus industry supported the concept of Argentine citrus
imports. Further, a new pest list based on the 1995 risk assessment and
updated with information provided by Argentina was sent for comment to
the State plant regulatory officials (SPRO's) in the citrus-producing
States of Florida, Louisiana, Texas, Arizona, and California in the
fall of 1996, and a draft of the 1997 quantitative pest risk assessment
was sent to those SPRO's in the spring of 1997. Each of the SPRO's was
encouraged by APHIS to circulate those documents as they saw fit. We do
not believe, therefore, that the proposed rule must be withdrawn in
order to comply with Executive Order 12866.
Comment: If APHIS allows Argentine citrus to enter the United
States without adequate protective measures in place, and the U.S.
citrus industry is then economically injured, APHIS' actions would rise
to the level of a ``taking'' of private property by an arm of the U.S.
Government.
Response: Because this rule places no limitations or restrictions
whatsoever on the U.S. citrus industry or individual U.S. growers or
their property, we do not believe that this rule constitutes a
regulatory taking.
Comment: In failing to establish quarantine-level treatments for
citrus black spot and sweet orange scab in the proposed rule, APHIS is
failing to meet its responsibilities for pest exclusion under the Plant
Quarantine Act and the Federal Plant Pest Act, which clearly charge the
Secretary of Agriculture with the responsibility for preventing the
entry of pests that are new to or not widely established in the United
States.
Response: Neither the Plant Quarantine Act nor the Federal Plant
Pest Act state that quarantine-level treatments are the only means
through which the Secretary may meet his responsibilities for pest
exclusion under those acts. Rather, 106 of the Federal Plant Pest Act
(7 U.S.C. 150ee) authorizes the Secretary to promulgate regulations
requiring the inspection of articles imported into the United States
and may impose ``other conditions upon such movement, as he deems
necessary to prevent the dissemination into the United States, or
interstate, of plant pests * * *.'' Quarantine-level treatments are not
available for all commodity/pest combinations; in the absence of such
treatments, we must consider whether alternative measures are available
that will provide a comparable level of quarantine security, and we
expect other nations to do the same with respect to U.S. agricultural
exports. In this rule, we require the use of tiered and overlapping
measures that, when combined with specified cold treatments or host
resistance, will reduce the pest risks associated with the importation
of Argentine citrus to a negligible level. We believe, therefore, that
we have met our responsibilities under the acts cited by the commenter.
Comment: APHIS' fruits and vegetables regulations only address the
importation of fruits and vegetables from countries where insect pests
are present; diseases are not addressed. It appears that APHIS does not
have the authority under its regulations to permit the entry of fruits
or vegetables from countries where one or more diseases exist.
Therefore, given that citrus diseases exist in Argentina, it appears
that APHIS does not have the authority under its regulations to
promulgate a regulation that allows the importation of grapefruit,
lemons, and oranges from that country.
Response: Our regulations are not the source of our authority to
regulate the importation of fruits and vegetables; rather, they are a
means through which we exercise the authority derived from statutes
such as the Federal Plant Pest Act and the Plant Quarantine Act. The
Secretary of Agriculture is provided with the authority in the Plant
Quarantine Act to restrict the importation of fruits and vegetables
because of ``injurious plant diseases or insect pests'' or to prohibit
such importation because of any ``disease or of any injurious insect''
(7 U.S.C. 159, 160). Therefore, we have clear statutory authority to
regulate the importation of fruits and vegetables because of diseases
as well as insect pests. With respect to our regulations implementing
the Secretary's authority under those acts, the commenter is correct in
noting that the fruits and vegetables regulations contain no general
provisions regarding diseases. However, the regulations in ``Subpart--
Citrus Fruit'' (Sec. 319.28), which we are amending in this rule and
which was discussed in the proposed rule, do in fact contain specific
restrictions on the importation of fruit of citrus and citrus relatives
from specified countries due to the presence of citrus diseases in
those countries.
Comment: The April 1992 pest risk analysis that APHIS completed for
its rulemaking regarding the importation of citrus from South Africa
states that ``[i]mportation of all plant parts, except seed, of Citrus
spp. should be prohibited from countries where the disease [black spot]
occurs'' (Pest Data Sheet on Black Spot of Citrus, p. 62). Yet, neither
the risk assessment nor the proposed rule for Argentine citrus mentions
that serious concern that the Agency had so recently expressed about
citrus black spot. It appears that APHIS is now proposing to make an
abrupt change in its position regarding this disease and the danger
that it poses without either articulating the reasons for this change
or including in the record substantial evidence that could support such
a divergence from longstanding agency policy.
Response: We disagree with the commenter's contention that we are
making an abrupt change in policy with regard to the risks presented by
citrus black spot. More importantly, our position regarding the
phytosanitary significance of citrus black spot has not changed as
drastically as the commenter suggests. We still consider citrus nursery
stock and plant parts other than fruit to pose a high risk as pathways
for the introduction of citrus black spot. It is only our position
relative to citrus fruit--specifically, citrus fruit that has been
subjected to the measures required by this rule--that has changed since
the April 1992 pest risk analysis for South African citrus. The pest
data sheet cited by the commenter was completed more than 5 years
before we prepared the Argentine citrus analysis and did not consider
the tiered and overlapping measures used in the systems approach to
mitigate the risk of citrus black spot; thus, the data sheet's
recommendations were made in the context of an importation scenario in
which no measures short of prohibition were offered to mitigate the
risk of citrus black spot.
[[Page 37614]]
APHIS' reading of the relative risks presented by citrus plants,
fruit, and other plant parts is consistent with the current research
into the epidemiology and control of citrus black spot and the evolving
scientific understanding of the disease. For example, Professor J.M.
Kotze of the University of Pretoria (South Africa) reports in a
Department of Microbiology and Plant Pathology summary of plant
pathology research focus areas that: ``We have shown that the disease
[citrus black spot] spreads to new areas through leaves of nursery
trees. The importance of the inoculum sources was already demonstrated,
especially the fact that fruit presents no danger to importers of
citrus in Europe.'' Fruit has been shown to be a poor pathway for the
introduction of citrus black spot, and, as explained in the proposed
rule, the required systems approach acts to reduce any remaining risk
to a negligible level.
Trade-Related Issues
Comment: In the proposed rule, APHIS stated: ``Maintaining a
prohibition on the importation of grapefruit, lemons, and oranges from
the Argentine States of Catamarca, Jujuy, Salta, and Tucuman in light
of those State's [sic] demonstrated freedom from citrus canker would
run counter to the United States' obligations under international trade
agreements and would likely be challenged through the World Trade
Organization'' (WTO). This is simply not true. Even if the four
involved Argentine States are free from citrus canker, there are other
potentially devastating citrus diseases and pests present. Under the
Uruguay Round WTO agreement, the United States has no obligation to
permit the introduction and spread of quarantine diseases and pests in
this country. Any country is free to adopt a ``zero risk'' standard as
its appropriate level of protection; we submit that the current U.S.
prohibition on fruit that is infected with sweet orange scab and citrus
black spot is entirely consistent with the Uruguay Round's ``Agreement
on the Application of Sanitary and Phytosanitary Measures'' (the ``S&P
Agreement''). Argentina has not shown that the importation of fruit
from an indisputably infected region poses no risk that sweet orange
scab, citrus black spot, or both, may be introduced into the United
States.
Response: We understand that we are not required to allow diseased
or infested fruit to be imported into the United States; indeed, this
rule does nothing to alter the ``current U.S. prohibition on fruit that
is infected with sweet orange scab and citrus black spot'' noted by the
commenter. However, we also recognize that we are obliged to use health
requirements only to the extent necessary to meet our ``appropriate
level of protection.'' In the case of grapefruit, lemons, and oranges
from Argentina, we believe that the tiered and overlapping safeguards
contained in this final rule will reduce the pest risk associated with
their importation to a negligible level. If the United States had
deemed ``zero risk'' to be its appropriate level of protection, then it
is unlikely that Argentine citrus--and many other commodities, for that
matter--would ever be approved for importation into the United States.
There will always be some degree of pest risk associated with the
movement of agricultural products; APHIS' goal is to reduce that risk
to a negligible level.
While the one sentence quoted by the commenter from the proposed
rule mentioned only citrus canker, we believe that it is evident from
the content of the entire proposed rule that we did indeed consider the
presence of other diseases and insect pests in Argentina. It should be
noted that the sentence quoted by the commenter was preceded by another
sentence in the proposed rule: ``We have rejected that alternative
[i.e., to make no changes in the regulations and continue to prohibit
the importation of grapefruit, lemons, and oranges from Argentina]
because we believe that Argentina has demonstrated that the citrus-
growing areas of the States of Catamarca, Jujuy, Salta, and Tucuman are
free from citrus canker and because we believe that the systems
approach offered by Argentina to prevent the introduction of other
plant pests reduces the risks posed by the importation of grapefruit,
lemons, and oranges to a negligible level.''
Comment: We submit that APHIS should consult with the U.S. Congress
on the issue of the ``appropriate level of protection'' in this
situation, especially given that the world trading community has yet to
settle the issue of what constitutes an appropriate level of
protection. The citrus industry is far too important to the United
States economy and trade interests for APHIS to make critical economic
and foreign policy decisions on its own, particularly when no
international standard dictates a particular result.
Response: The provisions of the WTO SPS Agreement provide that it
is the sovereign right of each member to set its own level of
protection, thus it would be inappropriate for the ``world trading
community'' to make such a determination. In this instance, APHIS, as
the recognized regulatory authority, is establishing a system of
phytosanitary measures that reflect the level of protection deemed
appropriate. It is our intent to allow fresh grapefruit, lemons, and
oranges to be imported into the continental United States from
Argentina only if they are grown, packed, and shipped under specified
phytosanitary conditions designed to mitigate the risk of plant pest
introduction. We are confident that the phytosanitary measures required
by this rule will mitigate the risk presented by Argentine citrus.
Given that confidence, we do not believe that the level of protection
afforded by this rule is a departure from the level of protection we
demand in other commodity import situations.
Comment: Article 6 of the S&P Agreement recognizes that countries
can have regions that are pest- or disease-free or have areas of low
pest or disease prevalence. However, it is envisioned that each country
claiming to have such regions has the burden of proving that such areas
have no pests or diseases or have low levels of pests or disease.
Argentina has not provided any information to APHIS as to the levels of
pests or diseases that are present in the four States that are proposed
for export.
Response: Argentina claims that the citrus-growing regions
identified in this rule are free from citrus canker, and we believe
that they have provided sufficient documentation to support that claim.
We also believe that Argentina submitted sufficient documentation to
support its position that the remaining pests and diseases were of low
enough prevalence that the chemical, cultural, and other controls of
the systems approach would prevent their introduction into the United
States on fruit imported under the requirements of this rule.
Comment: APHIS' regulations in Sec. 319.56-2 refer to ``without
risk,'' yet the proposed rule seems to have a standard on ``negligible
risk.'' Even if APHIS does have the statutory authority to adopt a
``negligible risk'' standard, the standard is undefined and impossible
to determine. This is not acceptable. The standard should be capable of
being independently validated and should be set only after rigorous
peer review, in accord with standards and guidelines adopted by WTO
with the advice of International Plant Protection Convention (IPPC).
Response: The ``without risk'' provision selected by the commenter
is found in Sec. 319.56-2(e) and is used in the context of importing a
fruit or vegetable from a definite area or district of a country that
is free from some or all of the injurious insects that attack the fruit
or vegetable when that area or
[[Page 37615]]
district meets the criteria for pest freedom found in Sec. 319.56-2(f).
Section 319.56-2(e) is not applicable to this rulemaking because the
Argentine Government has made no claims with regard to the freedom of
northwestern Argentina with regard to injurious insects i.e., fruit
flies in this case. The risk of diseases is addressed under the
regulations in Sec. 319.28 (Subpart--Citrus Fruit), which contains no
such ``without risk'' standard. In any event, we do not believe that a
policy of requiring imports to be ``without risk'' or to present ``zero
risk'' could be sustained by any country that wishes to engage in
international trade. There will always be some degree of pest risk
associated with the movement of agricultural products; APHIS' goal is,
and always has been, to reduce that risk to a negligible level. This
goal is entirely consistent with the standards and guidelines of the
WTO and the IPPC.
Comment: In the proposed rule, APHIS does not offer any ``reasoned
analysis'' for departing from its longstanding policy of not permitting
the importation of fruit from diseased regions. In its two recent
rulemakings regarding the importation of citrus from South Africa and
Australia, APHIS stated that it would deny the entry of citrus from
each of those countries if the citrus was found to be infected with
citrus black spot. It appears that it was clear to APHIS in those cases
that citrus black spot was so troubling and dangerous that the only way
to protect the United States against importation of this disease was to
disallow the importation of any fruit from diseased areas. The
inconsistency of APHIS' proposed approach to Argentine fruit with its
prior, recent positions regarding fruit from South Africa and Australia
is never mentioned or explained in the proposed rule or the risk
assessment. Further, the differences in the approaches applied to
Argentine citrus on one hand, and Australian and South African citrus
on the other, leaves the United States open to challenges from
Australia and South Africa under article 2.3 of the S&P Agreement,
which requires that member countries do not discriminate with respect
to other member countries where ``similar conditions prevail.''
Response: In the two rulemakings cited by the commenter regarding
the importation of citrus from Australia and South Africa, the freedom
of the production areas from citrus black spot formed part of the basis
for allowing the importation of citrus from those countries. Because
the importation protocols were based largely on that area freedom, it
follows that we would prohibit the importation of citrus from either
country if it was found to be infected with citrus black spot. In the
case of Argentine citrus, no such claim of area freedom is made, which
is why this rule requires control and detection measures for citrus
black spot. Because of these differences in the bases for the three
rules in question, we do not believe that this final rule arbitrarily
or unjustifiably discriminates between countries where similar or
identical conditions prevail. Further, it is important to note that
this final rule, like the Australian and South African citrus fruit
regulations, prohibits the importation of any fruit found to be
infected with citrus black spot.
Comment: The rate of importation of fruit into the United States
should be consistent with the rate of production of a normal lemon farm
as if trees were planted today. If I planted a lemon tree today, I
wouldn't receive any production for 3 years, and then production would
increase gradually through the tenth year. Regardless of current
Argentine production available for importation, no lemons should be
allowed into the United States during the first 3 years, and then only
15 percent the fourth year, 30 percent in the fifth year, etc., until
full production is allowed.
Response: APHIS has no authority to impose the quotas suggested by
the commenter.
Comment: APHIS should calculate the cost per field box to the
American farmer of the cost of U.S. Government regulation and adopt a
temporary tariff in that amount on all imported Argentine fruit. The
amount collected by the temporary tariff would be distributed to the
American lemon farmer based on each farmer's field box production until
Argentina adopts the same laws and regulations that the American farmer
must obey. The minimum-wage law, Labor Standards Act, and all
environmental and health safety laws are examples of such laws and
regulations.
Response: APHIS has no authority to impose the tariff suggested by
the commenter.
Comment: APHIS has no regulations that govern the procedure and
standards for consideration of import petitions filed by foreign
governments. Nor does the website maintained by APHIS provide any
information on the process for, or standards which are applied to, such
petitions. We submit that APHIS has an obligation to establish its
procedures and standards when dealing with plant diseases in such a way
as to provide the affected industry with confidence that agency
decisionmaking is being conducted in a ``reasoned'' way based upon
substantial evidence in the record and meaningful opportunity for
public comment.
Response: Foreign governments most often broach the subject of
exporting new fruits or vegetables to the United States through formal
negotiations or informal contacts with APHIS officials. These requests
and any subsequent detailed proposals are reviewed by APHIS staff
experts. After that review, APHIS staff may either recommend approval
of the petition or contact the petitioning government with a request
for additional research, proposed safeguards, etc. As noted by the
commenter, this government-to-government contact is not the subject of
any procedural regulations in part 319. However, the public is provided
the opportunity to review the Agency's basis for any change in the
regulations proposed as a result of a foreign government's import
petition. Each time we propose to amend our regulations to address an
import request that involves a new commodity/region combination, we
prepare a proposed rule that is commented upon by the public. In each
case, the proposed import program, including mitigation measures, is
clearly described in the proposed rule, and the rationale underlying
the proposed import program is explained. The public, which includes
any potentially affected industry, then has the opportunity to review
the proposed rule and its supporting information and may provide
comments that must be considered and addressed by APHIS before any
final action on a foreign government's import petition may be taken.
Systems Approach
Comment: APHIS' regulations contain no discussion, definition, or
description of what constitutes a ``systems approach,'' or what
treatment or treatments will qualify as an acceptable systems approach.
There are no standards in APHIS regulations that permit affected
parties to understand or judge the Agency's actions to approve or
disapprove such an approach. This is unacceptable. An agency is
obligated to set forth the standard the agency is applying or how it is
applying that standard to the factual situation.
Response: The standard that we apply to any potential import
situation is clear and has been well-established over the course of
numerous APHIS rulemakings dealing with the importation of agricultural
commodities: Does the importation of a particular commodity from a
particular region present a risk of introducing pests into the United
States,
robop...@us.govnews.org
Posting-number: Volume 65, Issue 116, Page 37607, Part 1
[[Page 37616]]
and, if so, can that risk be reduced to a negligible level through the
application of phytosanitary measures? These considerations are
addressed each time we propose to amend our regulations to address an
import request that involves a new commodity/region combination. In
each case, the proposed mitigation measures, which can range from
something as basic as inspection at the port of entry to a more
complicated systems approach of tiered and overlapping measures, are
clearly stated in the proposed rule, and the rationale for their
proposed use is explained. So, while the general provisions of our
regulations do not discuss, define, or describe what constitutes a
systems approach or what treatment or treatments qualify as an
acceptable systems approach, we do not believe that the lack of such a
discussion in the regulations detracts from the public's ability to
understand, assess, and comment upon the mitigation measures proposed
for a particular commodity/region combination.
Comment: Applying a systems approach to disease suppression for the
purpose of allowing imports from a region with a disease that does not
exist in the United States is a fundamental change in APHIS policy.
Previously, APHIS has always demanded that the area in which the crop
is grown be completely free of disease and geographically separated
from regions with the disease. This principle is applied to citrus
canker in the northwestern region of Argentina, but is not the case
with sweet orange scab or citrus black spot. There has not been a full
scientific discussion of the principles that need to be fulfilled
before moving forward with such a fundamental change in the standards
for U.S. quarantine pest protection. Therefore:
<bullet> APHIS should identify and cite the studies that have been
used to determine that a systems approach provides sufficient safety
from all kinds of plant pests when importing fresh produce into the
United States;
<bullet> APHIS should establish basic standards for the kind of
data and experiments that are needed to provide confidence in applying
the systems approach to disease control;
<bullet> APHIS should establish standards by which the information
used to determine the effectiveness and practicality of the systems
approach are to be judged; and
<bullet> There needs to be a public discussion of what level of
risk is appropriate.
Response: We believe that the commenter is incorrect in asserting
that APHIS is fundamentally changing its policy by not demanding that a
growing area be completely free of disease and geographically separated
from regions where disease exists. A long-standing precedent for the
local freedom concept is found in the citrus fruit regulations in
Sec. 319.28(b)(1), which allow Unshu variety oranges to be imported
into certain areas of the United States from Japan and South Korea if
the oranges are grown in citrus-canker-free export areas that are
surrounded by 400-meter buffer zones. While the Unshu orange program
differs from the Argentine citrus program in many respects, the fact
remains that the Unshu orange program stands as an example of a
successful approach to importing fruit from regions where a disease
exists.
As noted in the response to the previous comment, it is true that
the general provisions of our regulations do not discuss, define, or
describe what constitutes a systems approach or what treatment or
treatments qualify as an acceptable systems approach. However, we do
not believe that the lack of such a discussion in the regulations
detracts from the public's ability to understand, assess, and comment
upon the mitigation measures proposed for a particular commodity/region
combination because, in each case where we propose to allow the entry
of a new commodity, we explain the proposed mitigation measures and
provide the scientific rationale underlying their proposed use. Thus,
the public has the opportunity to judge each proposed importation
according to the criteria suggested by this commenter.
The commenter states that ``APHIS should identify and cite the
studies that have been used to determine that a systems approach
provides sufficient safety from all kinds of plant pests when importing
fresh produce into the United States.'' We are unaware of any studies
that examine the use of systems approaches as broadly or definitively
as the commenter suggests; there are simply too many possible
combinations of pests and hosts on one hand, and biological, physical
and operational factors that could be integrated into a systems
approach on the other, to allow for such a conclusive determination.
Thus, while it is acknowledged that systems of practices and procedures
can be assembled to provide quarantine security in many cases, each
proposed use of a systems approach must be evaluated individually. We
will, however, consider the commenter's suggestion that we establish,
to the extent possible, general standards for the preparation and
evaluation of data that serve to support the establishment of systems
approaches. Finally, the commenter states that there needs to be a
public discussion of what level of risk is appropriate; we believe that
the comments received in response to our proposed rule are one
indication that such a discussion of the level of risk that APHIS has
determined to be approporiate is already open and ongoing. Given the
numerous, evolving, and unpredictable factors affecting the perception
of, and tolerance for, risk, it appears that the ``public discussion of
what level of risk is appropriate'' will, by necessity, be an ongoing
exchange rather than a discrete deliberation.
Comment: APHIS has never before proposed using a systems approach
for a combination of diseases and insect pests. What is particularly
troubling about the approach APHIS is proposing in the Argentine rule
is that the Agency has issued this proposal with no specific discussion
of its rationale; its only stated justification is the previous use of
system approaches. However, previous systems approaches are similar in
only the most remote of ways and are not at all similar in execution or
in impact. Thus, the Agency must set forth a detailed justification
supported by sound scientific evidence for this fundamental shift in
regulatory approach. Further, we submit that APHIS should have adopted
this expanded use of a systems approach only after conducting a notice
and comment process, with rigorous scientific peer review to determine
whether a systems approach can be an effective tool when addressing
diseases.
Response: It is not true that we sought to justify the use of a
systems approach for Argentine citrus by pointing to previous uses of
systems approaches; indeed, the proposed rule did not mention the use
of a systems approach in any context other than that of Argentine
citrus. Further, we disagree with the commenter's contention that we
issued the proposed rule ``with no specific discussion of its
rationale.'' Our rationale for the use of a systems approach for
Argentine citrus was stated early in the proposed rule, at the end of
the first paragraph under the heading ``Importation of Grapefruit,
Lemons, and Oranges,'' where we stated ``To prevent the introduction
into the United States of those diseases [i.e., sweet orange scab and
citrus black spot] and fruit flies, the Government of Argentina, with
the cooperation of APHIS, has formulated a systems approach of tiered
and overlapping measures that, when combined with specified cold
treatments, would reduce the risks presented by those pests to a
negligible
[[Page 37617]]
level.'' The proposed rule then explains in detail each of the
phytosanitary measures that would be required in order for citrus to be
exported to the United States from Argentina. That explanation, we
believe, constitutes the ``detailed justification'' requested by the
commenter. We do not believe that our application of systems approach
principles to the importation of Argentine citrus is in any way a
departure from our policy of allowing the importation of fruits and
vegetables when the risks presented by those commodities can be
mitigated to a negligible level.
Comment: The systems approach is premised upon the layering of
several risk reduction measures. An effective verification and
enforcement system is essential for the layering of risk reduction
measures to result in the desired outcome. What will be done when one
or more of these layers beaks down? APHIS should have a response plan
for action when a risk reduction measure fails.
Response: The systems approach contained in this rule, as is the
case with all systems approaches contained in APHIS' regulations, is
indeed premised upon the layering of several risk reduction measures.
The tiered and overlapping nature of any systems approach ensures that
even if any one of the elements of the systems approach is omitted or
fails, and that omission or failure remains undetected, adequate
measures will remain to provide the necessary level of phytosanitary
security. Further, we agree that an effective verification and
enforcement system is essential to the success of any systems approach.
To achieve that success, this rule requires that SENASA actively
participate in or supervise each step of the process in Argentina to
verify and document each step's successful completion or application,
and the required documentation must be made available to APHIS.
Further, as discussed earlier in this document in the paragraph titled
``Monitoring--Argentina,'' the operational work plan that addresses the
administration of the export program will include provisions for active
and direct monitoring of the program by APHIS personnel who will
conduct frequent oversight visits to the growing areas and
packinghouses in order to observe each step of the program in
Argentina. Further, each shipment of fruit must be accompanied by a
phytosanitary certificate issued by SENASA that verifies that the fruit
was produced and handled in accordance with the requirements of
Sec. 319.56-2f(a) through (c) and that the fruit is apparently free
from citrus black spot and sweet orange scab. Fruit that fails to meet
those requirements will not be eligible for importation into the United
States. At the port of entry in the United States, APHIS will inspect
the fruit and its accompanying phytosanitary certificate and will
confirm that any required cold treatment has been properly applied.
Finally, the detection of citrus black spot or sweet orange scab on any
grapefruit, lemons, or oranges at any time in Argentina, during
transport, or in the United States will result in the grove in which
the fruit was grown or is being grown being removed from the SENASA
citrus export program for the remainder of that year's growing and
harvest season, and the fruit harvested from that grove being
ineligible for importation into the United States from the time of
detection through the remainder of that shipping season.
Comment: For a systems approach to be effective, it is essential to
know the biological interactions between the pest and its host to
understand how these interactions affect production, shipment, and
marketing of commodities. There is very little current knowledge about
citrus black spot or sweet orange scab, and virtually no work has been
done on the question of how the diseases would respond if brought into
the United States. Thus, there is a substantial threshold question of
whether a systems approach can even be designed to deal with citrus
black spot or sweet orange scab.
Response: As neither of those diseases is present in the United
States, it is not unusual that most researchers in this country who
study citrus crops and their pests have directed their efforts to
other, more immediate concerns. However, in countries where citrus
black spot or sweet orange scab is present and where citrus is an
economically important crop, those diseases have been, and continue to
be, the subject of focused research. We believe that the information on
the prevention, control, and detection of these diseases that has been
collected over the years, combined with the results of the field trials
conducted in Argentina, provides the necessary degree of scientific
support for the systems approach described in this rule.
Comment: APHIS has not used a systems approach previously in a
situation where the intended result of the treatments is simply
suppression of the symptoms of the disease(s) in a proposed export
area. Thus, proposing to rely on an approach which admittedly only
results in suppression of the symptoms of the diseases is a fundamental
policy shift by APHIS. The proposal also stands in stark contrast to
the goal of complete eradication of a disease, which has been and
remains the objective in every situation in the United States where a
plant disease or pest does exist. As such, any contemplated use of such
an approach should be subjected to the most rigorous, exhaustive, and
comprehensive level of scientific peer review.
Response: The intended result of the treatments, particularly the
oil-copper oxychloride sprays during the growing season, as well as
measures such as grove cleaning to remove inoculum, is the prevention
of infection, and not simply the suppression of symptoms as stated by
the commenter. Other required measures are specifically designed to
detect the presence of diseased fruit and prevent its importation into
the United States. Given that the goal of this rule is to provide for
the importation of disease--free and not simply asymptomatic--
grapefruit, lemons, and oranges, we do not believe that this rule
represents a departure from our policy of allowing the importation of
fruits and vegetables when the risks presented by those commodities can
be mitigated to a negligible level.
Comment: A publication titled Quarantine Treatment for Pests of
Food Plants (edited by Jennifer L. Sharp and Guy J. Hallman, Westview
Press, 1994), includes a discussion of systems approaches that stresses
the importance of determining the level at which a pest or disease
exists in order to design an effective systems approach. Nothing on the
record of the Argentine proposed rule indicates the ``level of
infestation'' of the host fruit by any of the diseases or pests at
issue. This infestation information must be known before APHIS can even
consider the possibility of designing a systems approach. Only when
this infestation level is known can the efficacy of the proposed system
be judged. Without this information, interested parties are unable to
conduct any meaningful review of the proposed systems approach.
Response: The ``level of infestation'' passage noted by the
commenter is found on page 226 of the cited publication and states ``*
* * [S]ystems recognize that the commodity in question is a host, the
level of infestation in the host being the key component in the design
of the overall system. Systems rely on knowledge of the infestation
level of the host and measure the impact of the various operational
procedures on removing infested hosts, thereby reducing the risks that
infested hosts will be shipped.''
[[Page 37618]]
For the fruit flies of concern in Argentina, a single quarantine
treatment--cold treatment--is available and is required by this rule,
which leaves citrus black spot and sweet orange scab as the ``diseases
or pests at issue.'' Surveys produced by Argentina show that disease
incidence--i.e., the ``level of infestation'' referred to in the cited
publication--varies from season to season, depending on the prevailing
environmental conditions, and can be high in untreated groves. The
results of those surveys were reported in the risk assessment that
accompanied the proposed rule, so there is in fact information on the
record indicating our knowledge of disease incidence in Argentina.
Because of the known seasonal variations in disease incidence, the
design of the systems approach for Argentine citrus began with the
assumption of a potentially high ``level of infestation'' and set out,
through biological and operational factors such as buffer zones,
inoculum removal, inspections, testing, and treatments, to reduce the
risks of infected fruit being shipped to the United States.
Comment: It is not possible to properly assess the adequacy of a
systems approach in preventing the introduction of pests into an
importing nation without detailed knowledge of the circumstances under
which a pest occurs, and the frequency with which it occurs, in the
export region. APHIS' current risk assessment is based on a poor body
of knowledge of insect species present or potentially present in
Argentina, particularly the Anastrepha species present in northwestern
Argentina. Further, the level of pesticide use there could be masking
the presence of lesser-known pests that could emerge as a problem if
newer, more specific pesticides are used in Argentina. Therefore,
extensive taxonomic research and population surveys on fruit flies and
other insect species present in northwestern Argentina, as well as data
on other potential hosts in that region, are necessary in order for a
proper risk assessment to be completed on Argentine citrus and for the
systems approach to be fully evaluated.
Response: Citrus is an economically important crop in Argentina,
and as such has been, and continues to be, the subject of well-
supported and vigorously pursued research into its production and
factors affecting that production, including pests. We are confident,
therefore, that the pest list produced by SENASA, which was reviewed by
APHIS and by agricultural officials in the four main citrus-producing
States of this country and compared against reports from various
international sources and the scientific literature, accurately
addressed the range of citrus pests present in Argentina. Further, we
believe that the risks posed by those pests were adequately considered
in the risk assessment and addressed by the provisions of this rule.
Comment: What is the goal of the systems approach for citrus black
spot and sweet orange scab? Some of the statements in the rulemaking
record imply that the goal is to have disease-free groves, while the
proposed rule seems to seek the suppression of disease symptoms in
export groves. Recent statements by APHIS imply that it would be
acceptable for diseased fruit to enter the United States.
Response: The goal of the systems approach is to reduce the plant
pest risks associated with the importation of Argentine citrus to a
negligible level. With regard to citrus black spot and sweet orange
scab, the systems approach is designed to accomplish that goal through
both prevention and detection; the grove cleaning and growing season
spraying requirements are designed specifically to prevent fruit from
becoming infected in the first place, and subsequent surveys,
inspections, and testing provide multiple opportunities for the
detection of infected fruit. If a single infected fruit is found at any
point in the process, including inspections conducted after the fruit
has arrived in the United States, the grove in which that fruit was
grown will be removed from the SENASA citrus export program and the
fruit harvested from that grove may not be imported into the United
States from the time of detection through the remainder of the shipping
season. Thus, the commenter's impression that we would find it
acceptable for diseased fruit to enter the United States is incorrect.
Comment: The record of data supplied by Argentina, as provided to
the public by APHIS, is completely inadequate to assess the efficacy of
the individual measures, let alone the systems approach, for citrus
black spot and sweet orange scab. Either APHIS has not maintained a
complete record of the information Argentina supplied, or the Agency is
basing its risk estimates on ambiguous data because of inadequate
reporting by Argentina.
Response: We have, in fact, maintained a complete record of the
information supplied by Argentina, and we did share that information
with the commenter, although we were unable to provide the information
that was the subject of the commenter's FOIA request until after the
close of the comment period. Further, it is important to note that our
assessment of the risks presented by Argentine citrus and of the
efficacy of specific measures was not based solely on the material
provided by Argentina; information gathered from other sources and the
expert judgment of subject matter specialists also played a role. This
is the norm when conducting probabilistic assessments to inform
decisions regarding importation of agricultural commodities. When data
that represent ``direct evidence'' do not exist, which is often the
case in probabilistic risk assessments, available information is
reviewed and applied through the use of professional judgment. APHIS
bases the estimates needed for its probabilistic commodity risk
assessments on pest interception records, the known biology of the
organism being assessed (or the known biology of related taxa) as
represented in the scientific literature, expert judgment based on
laboratory experience with the pest or related organisms, expert
judgment based on field experience with the pest or related organisms,
expert judgment based on experience conducting commodity inspections at
ports of entry or in the exporting country, and experience working with
export programs and export-quality commodities. Thus, we believe that
the entire body of information available is, in fact, sufficient to
support the efficacy of the measures required by this rule and our
analysis of the risks associated with Argentine citrus.
Comment: The following items are examples of the type of data or
information that appear to be missing from the rulemaking record. No
information is provided as to what the climatic conditions were in the
tested groves during the spraying program. Similarly, no information is
provided on how the spraying program would be affected by different
climatic conditions in different growing areas, such as the
northwestern versus the southern part of Tucuman, and Tucuman as
compared to Salta, etc. Accordingly, it was impossible to answer many
critical questions: Was it a year of light incidence of the disease,
and thus the spraying was very effective? What would happen in a year
of heavy incidence? What were the ages and varieties of the trees in
the program? What was the protocol that was followed? How would
different climatic conditions affect the spraying program? Would the
same results have been achieved if the trees had been 10 years older?
Neither the risk assessment nor the rulemaking record addresses or
answers any of these questions. APHIS must require much more extensive
tests
[[Page 37619]]
covering multiple variables before further considering the Argentine
petition. Variables that should have been included in tests before
approving the Argentine petition would include, but are not limited to:
Multiple and differing climatic situations (i.e., drier versus more
humid areas; more humid years versus drier years); differing ages of
trees, since citrus black spot is more often seen in older trees and in
ripe fruit; differing sizes of groves; whether the grove was virtually
surrounded by untreated groves; whether the trees had been under any
type of stress; etc.
Response: The bioecological factors affecting citrus black spot
development that were considered in the design of the field testing
conducted in Argentina, the protocols for the field tests, and the
results of those tests are among the material provided to the commenter
in Note S.P. 338 of December 5, 1995, and its three annexes
(``Bioecology of Black Spot in Citrus,'' ``Field Assays for the Control
of Black Spot in Citrus,'' and ``Results of the Postharvest Assays
Carried Out up to the Present''). These documents demonstrate that
Argentina recognized, and took into account, that factors such as
climate, humidity, fruit susceptibility, and the presence of inoculum
have an effect on the presence of the disease. The Argentine field
tests were conducted during growing seasons marked by both dry
conditions with light disease incidence in control trees and prolonged
rainy conditions with a heavy incidence of disease in control trees.
This information, which was used in the design of the systems approach,
was also considered by the experts who prepared the risk assessment. As
noted elsewhere in this document, the systems approach is designed to
mitigate the risk of citrus black spot during years in which the
disease is likely, which is why this rule requires in part that the
timing of the fungicidal sprays be determined by SENASA using an expert
system that takes climatic data, as well as fruit susceptibility and
the presence of disease inoculum, into account. We believe that the
body of information contained in the rulemaking record, including the
research and testing data provided by Argentina, provides the necessary
scientific and rational basis for our regulatory decisionmaking.
Comment: The evidence that APHIS has made available to date is
inadequate to support the proposed rule. The Secretary should appoint
an independent scientific team to travel to the proposed Argentine
production area when climatic conditions are appropriate, and that team
should be given access to the production and packing facilities, as
well as to the transportation and port operations that would be
utilized for the export program. The Secretary should direct that team
to report its findings to the Department and Congress.
Response: APHIS, under the authority of the Plant Quarantine Act
and the Federal Plant Pest Act, has reviewed the Argentine petition and
has made the determination that phytosanitary measures that comprise
the systems approach reduce the pest risk to a negligible level. The
systems approach that is the subject of this rule was developed in
Argentina by that country's plant health officials and citrus interests
and was presented, along with its supporting data, to APHIS for review.
APHIS rejected Argentina's initial proposal on the grounds that it did
not sufficiently mitigate the pest risk presented by Argentine citrus.
It was only after Argentina included additional phytosanitary measures
in its systems approach and provided what we determined to be an
adequate amount of additional efficacy data that APHIS accepted the
Argentine proposal. The Secretary is not required to appoint an
independent scientific team as suggested by the commenter, nor do we
believe that one is needed in light of the review already conducted by
APHIS.
Comment: The 1997 risk assessment states that the level of visible
incidence of citrus black spot can be extremely high in Argentina--as
high as 82 percent and can vary greatly year to year. This level of
disease incidence is disturbingly high. Further, this data does not
address the phenomenon of symptoms that remain latent. Based on the
current state of science, we submit that no fruit from such highly
diseased areas should be allowed to enter the United States.
Response: The section of the risk assessment cited by the commenter
stated that in untreated export-area orange groves, field surveys for
citrus black spot in 1994 and 1995 found 14 percent and 82 percent,
respectively, of sampled fruit were infected with the citrus black spot
fungus, and a similar 1996 survey found that 56 percent of the sampled
trees in an untreated lemon grove bore fruit with citrus black spot
symptoms. The risk assessment further states, however, that in the 1994
survey, citrus black spot incidence was reduced from 14 percent in
control groves to 0 percent in treated orange groves; in the 1995
survey, citrus black spot incidence was reduced from 82 percent to 11
percent; and in the 1996 lemon survey, none of the trees sampled in
treated groves bore fruit with citrus black spot symptoms. These tests
show that the incidence of citrus black spot can be significantly
reduced by orchard treatments, which is just one aspect of the systems
approach, even when the level of disease in the area is high. The issue
of asymptomatic, latently infected fruit is addressed by the rule's
requirement that a sample of fruit collected according to a
statistically valid sampling protocol be held for 20 days under
conditions that are ideal for producing symptoms in infected fruit. We
believe that this rule provides an array of effective measures to
reduce to a negligible level the risk of introducing citrus black spot
into the United States.
APHIS Involvement
Comment: The proposed rule does not provide for APHIS personnel to
perform any of the required inspections in Argentina. APHIS personnel
should inspect all groves according to a detailed protocol, and the
Argentines should pay all costs associated with such inspections.
Response: APHIS routinely relies upon the national plant protection
organizations of exporting countries to provide the supervision or
certification of phytosanitary measures that might be required for
specific agricultural commodities, just as other countries rely upon
APHIS to provide such services. We have had the opportunity to work
with SENASA on numerous phytosanitary issues in the past and, as a
result, we have every confidence in SENASA's ability to administer and
supervise the citrus export program established by this rule. SENASA,
as the national plant protection organization of Argentina, has a well-
established infrastructure in place throughout the country. Also,
SENASA personnel were involved at every step in the development of the
systems approach, so they are as familiar as APHIS with its
requirements. Further, SENASA personnel possess a level of familiarity
with Argentine groves, growers, and citrus production that APHIS
personnel do not. Given these considerations, we do not believe that
any appreciable advantage would be gained, from a plant protection/risk
reduction perspective, by requiring Argentina to pay for APHIS to
establish a new operational presence in that country. However, as
discussed earlier in this document in the paragraph titled
``Monitoring--Argentina,'' the operational work plan that addresses the
administration of the export program will include provisions for active
and direct monitoring of the program by APHIS personnel who will
conduct frequent oversight visits to the growing areas and
packinghouses in order to observe each step of the program in
Argentina.
[[Page 37620]]
Comment: APHIS does not have a sufficient number of employees
stationed in Argentina to provide an adequate level of monitoring for
the proposed export program.
Response: As noted in the response to the previous comment, we have
every confidence in SENASA's ability to administer and supervise the
citrus export program established by this rule. Accordingly, this rule
does not require direct APHIS supervision of the activities of the
citrus export program carried out in Argentina, so APHIS staffing in
that country is not an issue. While APHIS personnel will travel to the
production areas in order to monitor the progress of the export
program, especially during the first season, this rule provides for the
direct supervision of the measures required in Argentina to be carried
out by SENASA.
Origin Requirement
Comment: The proposed rule does not provide for annual surveys on
citrus canker. Such surveys should be made, records should be kept, and
audits should be required.
Response: Argentina has an ongoing monitoring program, as well as
quarantine protection systems, for citrus canker that have been in
place since 1992. Because Argentina's monitoring program is conducted
in accordance with United Nations' Food and Agriculture Organization
(FAO) standards, which include reporting and recordkeeping
requirements, we do not believe that it is necessary for this rule to
impose additional or redundant requirements regarding citrus canker
surveys.
Comment: If APHIS allows the importation of Argentine citrus, it
should impose movement restrictions on Argentine citrus similar to
those of its domestic citrus canker regulations.
Response: Our domestic citrus canker regulations apply to fruit
grown or packed in areas that are quarantined due to the presence of
citrus canker. Because it has been established in accordance with
international standards that northwestern Argentina is free of citrus
canker, such movement restrictions are neither necessary nor
justifiable.
Comment: According to the risk assessment, the median chance of
citrus canker becoming established in the United States with no pest
mitigation program is estimated as 1 chance in 4 trillion per year. The
extremely low value for this risk estimate can partially be attributed
to the fact that northwestern Argentina is assumed to be free of citrus
canker. However, even if it is assumed that 100 percent of the boxes of
fruit were initially infected (instead of the average of 0.05 percent
assumed in the risk assessment), the likelihood of citrus canker
establishing itself in the United States would be 1 in 2 billion per
year, according to the analysis performed by APHIS. If it is really
this improbable that citrus canker will become established in the
United States, why does the risk assessment even address citrus canker?
Why does the United States currently prohibit the importation of citrus
fruit from countries where citrus canker occurs and regulate the
interstate movement of citrus fruit from infested areas of the United
States? On the one hand, APHIS states that no outbreak of citrus canker
has ever been traced to the importation of fruit, and hence estimates a
very low probability that citrus canker will occur. In contrast, the
risk assessment's pest data sheet indicates that citrus canker can
potentially move long distances on diseased fruit, that at least three
outbreaks of citrus canker have occurred in the United States within
the past 100 years, and that there is currently citrus canker in
Florida. This information seems to indicate a risk greater than 1 in 2
billion per year, and suggests that the quantitative estimate is
incorrect.
Response: The fact that northwestern Argentina has been
demonstrated to be free of citrus canker in accordance with
international standards was an important factor in our assigning an
``extremely low value for this risk estimate.'' Another important
factor in that risk estimate is the evidence that the long-distance
spread of citrus canker has occurred primarily through the movement of
infected planting and propagating materials. The commenter reports that
the pest data sheet indicates that the pathogen could potentially move
long distances on diseased fruit, but omits the second half of the
sentence in which that statement appears, wherein we report that there
is no authenticated example of a disease outbreak that initiated from
diseased fruit. Given the preponderance of evidence and expert opinion
that long-distance spread occurs primarily through the movement of
infected planting and propagating materials, and given the absence of
documented cases of citrus canker outbreaks attributable to the
movement of infected fruit, we believe that the probability calculated
by the commenter is actually not unreasonable and our assessment of the
risk posed by citrus fruit from the citrus-canker-free States of
northwestern Argentina is appropriate. The larger question of whether
citrus canker may be spread long distances on diseased fruit has not
been answered to the satisfaction of some in the citrus production and
research communities, which accounts for our continuing restrictions on
the importation and interstate movement of citrus fruit from areas
where the disease occurs.
Comment: If the fruit from northwestern Argentina passes through
that country's eastern regions, which are not free from citrus canker,
it is possible that the fruit could be contaminated by airborne citrus
canker bacteria during transport.
Response: As stated in the pest data sheet for citrus canker
provided in the risk assessment, short-distance dispersal of the
pathogen in groves occurs primarily by wind-driven rain (rain and wind
in excess of 6--8 m/sec) that causes the water soaking in leaves
necessary for infection and causes entrance wounds when shoots are
injured by wind whipping. The pest data sheet also notes that overhead
irrigation may also play a role in short distance spread, as may
mechanical equipment used in grove maintenance (Ferguson, et al., 1985;
Swings & Civerolo, 1993). Given that citrus fruit traveling from the
packinghouses in the production areas will be boxed, with those boxes
being protected from the elements to prevent damage, we do not believe
that there is any appreciable risk of the fruit being contaminated by
airborne citrus canker bacteria during transport.
Comment: In a 1994 report that is part of the rulemaking record,
APHIS personnel who visited Argentina stated that they had concerns
regarding an apparent lack of inspection at the local airports with
regard to citrus canker. Has this issue been satisfactorily addressed?
Response: This issue was addressed following APHIS' 1994 trip.
Argentina has established quarantine control stations at all main
entrances to the citrus-canker-free States, including quarantine
checkpoints at local airports.
Comment: Although it is claimed that the four States of
northwestern Argentina listed in the proposed rule are free from citrus
canker, it may be that citrus canker does actually exist in those
States but is inhibited by warm temperatures and dry climate.
Response: Argentina's monitoring system for citrus canker consists
of inspections and systematic sampling carried out annually in all
production areas as well as in urban areas and nurseries. The collected
samples are analyzed at university and research center laboratories
using a high-sensitivity immunofluorescence serologic technique. Since
this monitoring system was implemented in
[[Page 37621]]
1992, no evidence of citrus canker has been found. We are, therefore,
confident that citrus canker is not present in the four northwestern
Argentine States.
Grove Requirements
Comment: The 150-meter buffer zone appears to be inadequate for
mitigating the spread of citrus black spot spores dispersed long
distances by the wind.
Response: The buffer zone is designed to reduce to an insignificant
level the possibility that ascospores from an infected grove would
reach a grove producing fruit for the U.S. market. The ascospores are
the only wind-dispersed propagule of black spot and are produced in
leaves on the ground, usually under the tree canopy. Environmental
conditions must be correct for ascospores to be dispersed (i.e., rain
to promote the release of the ascospores followed by sufficient wind to
move the ascospores from under the overhanging canopy of the tree). The
combination of the prevention of long-distance movement by the canopy
itself and the presence of a 150-meter buffer that, like the export
area of the grove, must be cleaned of all fallen leaves and other
debris before blossom, will significantly reduce the unlikely
possibility that ascospores from outside the area of production will
reach the production area. Additionally, because environmental
conditions are monitored and control methods are utilized during
periods when the developing fruit is susceptible to infection, the
likelihood of successful infection is negligible.
Comment: The risk assessment claims all new citrus stock in the
canker-free area must originate within the zone (which we assume to
mean the canker-free area) or be tissue culture that has passed through
quarantine, whereas the proposed rule only requires new citrus stock
planted within the export groves to meet those requirements. Does the
risk assessment therefore overestimate the protection offered by this
measure?
Response: The citrus stock origin requirements referred to by the
commenter as being in the risk assessment are existing requirements
established and enforced by SENASA as part of that agency's program to
maintain the citrus-canker-free status of the northwestern Argentine
States. SENASA's citrus stock origin requirements apply to all groves
in the citrus-canker-free area of Argentina; therefore, the risk
assessment's characterization of those requirements is correct and does
not overestimate the protection offered by those requirements. Because
the requirements of this rule pertain only to groves that produce fruit
for export to the United States, the rule does not extend those
requirements to other groves producing fruit for other export markets
or for domestic consumption within Argentina.
Comment: The proposed rule provides that any new citrus planting
stock used in a certified grove must originate from one of the four
States or from a SENASA-approved propagation center (Sec. 319.56-
2f(b)(3)). It is not clear whether this requirement goes only to citrus
canker, or whether it also applies to citrus black spot and sweet
orange scab. If it does not apply to citrus black spot and sweet orange
scab, what precautions will be taken to insure that planting stock does
not carry these diseases from within the approved areas? Evidence must
be included in the record that such precautions will be effective.
Response: As explained in the response to the previous comment, the
citrus stock origin requirements are part of SENASA's program to
maintain the citrus-canker-free status of northwestern Argentina. Thus,
those requirements apply only to citrus canker, and not to citrus black
spot or sweet orange scab. Because this rule is not based on the four
northwestern Argentine States being a free area for citrus black spot
or sweet orange scab, it was not necessary to include provisions for
the freedom of planting stock from those two diseases.
Comment: The preamble to the proposed rule states that domestic-
origin citrus plants must meet ``strict phytosanitary requirements''
before they may enter the four States that will be allowed to export.
Is this reference to the SENASA requirements for a propagation center?
Response: Yes. The requirements referred to in the preamble of the
proposed rule pertain to the testing and grow-out regimen conducted at
SENASA-approved citrus stock propagation centers for citrus stock that
has been imported into Argentina and for any domestic-origin citrus
plants from outside the four citrus-canker-free States. As stated in
the proposed rule, citrus plants from sources outside the citrus-
canker-free area ``must meet strict phytosanitary requirements before
they may enter the States of Catamarca, Jujuy, Salta, or Tucuman. Under
SENASA supervision, such citrus plants are officially tested to ensure
their freedom from quarantine pests and diseases, and are grown in
quarantine before being released for use in the citrus canker-free area
of Argentina.''
Comment: The preamble implies that nursery stock will be
``tested.'' However, citrus black spot is a latent disease. Can it be
successfully detected years in advance of when it appears? If tests
cannot be carried out, what precautions will be taken to ensure that
stock that may be from groves infected with sweet orange scab or citrus
black spot is not planted in noninfested groves? Answers to these
questions do not appear in the rulemaking record. Without such answers,
APHIS should not proceed with the proposed rule.
Response: As noted previously, SENASA's requirements, and the
requirements of this rule, pertaining to planting stock are intended to
prevent the introduction of citrus canker into the citrus-canker-free
area of northwestern Argentina; because the four Argentine States are
not a free area for citrus black spot or sweet orange scab, those
measures are not intended to provide protection against citrus black
spot or sweet orange scab introduction via nursery stock. The risks
presented by those two diseases are instead mitigated by the pre-and
post-harvest treatment and inspection requirements of this rule.
Comment: The risk assessment speaks only of the removal of fallen
fruit and leaves in the grove, but implies immediate and continuous
removal. The proposed rule considers fallen fruit, leaves, and branches
in both grove and buffer zone, but specifies removal only before
blossoming in the grove (but not necessarily before blossoming in the
buffer zone, or in any regions outside the buffer zone). If the buffer
zone contains fruit blossoming earlier than the grove, the fruit is
more likely to become infected if there is contaminated material
remaining on the ground, but such infection is less likely to be
observed/reported.
Response: The buffer zone immediately surrounds the grove--indeed,
it would be part of the grove if the owner was not producing fruit for
export to the United States--so it is not likely that the trees in the
buffer area will be blossoming any earlier or later than the trees in
the export portion of the grove.
Comment: The proposed requirement for the removal of all fallen
fruit, leaves, and branches from the orchard floor and the buffer area
is not a biological, well-justified safeguard. Research on attempts to
decrease incidence in other, similarly dispersed diseases through
cleaning of groves indicated that, while leaf and fruit removal could
remove about 90 percent of the inoculum, the 10 percent of inoculum
still present was more than sufficient to maintain the presence of the
disease. It is very likely that ascospore inoculum will remain in the
ground and any out-of-season or
[[Page 37622]]
late-hanging fruit will supply additional inoculum.
Response: The removal of fruit, leaves, and branches from the
orchard floor and buffer area is a biologically justified safeguard.
Because the ascospores of citrus black spot are produced only in fallen
leaves, the removal of this debris will significantly reduce the
inoculum level. This is a part of a control strategy that is used by
plant pathologists for diseases for which inoculum is produced in
fallen debris. Because this is only one part of a systems approach, it
is designed to reduce the likelihood of infection, not prevent it
entirely. Therefore, we have taken into account in the risk analysis
the possibility that debris may remain on the ground or in late season
fruit.
Comment: The proposed rule requires that export groves be cleaned
of debris, leaves, and fallen fruit before bloom to remove the main
sources of disease inoculum. Argentine researchers monitored leaf fall
during a whole season and found that for all three citrus species in
Salta, the majority of leaves fell between August and November, while
fruit set occurred from September to October. Thus, the maximum leaf
fall is occurring during bloom and fruit set. Furthermore, the summer
rains, which are needed for development of citrus black spot on the
dead leaves, tend to start in October. If decreasing inoculum through
removal of fallen leaves is the goal to protect the developing fruit,
then there must be continuous cleaning of the grove throughout the
maximum leaf fall period, otherwise fruit will be developing in the
presence of leaf litter as a potential source of inoculum.
Response: A thorough cleaning of the grove and buffer area prior to
blossom will remove a significant amount of potential inoculum. Any
ascospores on leaves that fall after the cleaning of the grove will not
form ascocarps until 40 to 180 days after blossom, depending on the
frequency of wetting; by that time, the preventive oil-copper
oxychloride sprays will be in use to protect the developing fruit from
infection. If the removal of fallen fruit, leaves, and branches was the
only measure employed to reduce the risk of citrus black spot infection
during the growing season, additional cleaning would likely be
advisable, but given the additional requirements of this rule, we do
not believe that is necessary.
Comment: The proposed requirement for the removal of all fallen
fruit, leaves, and branches from the orchard floor and the buffer area
would be difficult, if not impossible, to satisfy. We suggest that the
word ``substantially'' be inserted before the word ``all'' to make this
requirement more realistic.
Response: Although the grove/buffer sanitation requirement may be
difficult to meet, SENASA and the growers in northwestern Argentina
have indicated their willingness to comply with that requirement.
Further, it would likely prove difficult to establish a standard for
what is meant by ``substantially all.''
Comment: The proposed grove-cleaning would be a difficult, if not
impossible, task to complete. The proposed rule does not explain what
criteria will be used to verify the orchard floor cleaning and how it
can be verified at a later date.
Response: The proposed rule and this final rule state that SENASA
must inspect the grove and buffer area before blossom to verify that
all fallen fruit, leaves, and branches have been removed from the
ground. In the phytosanitary certificate required by paragraph (d) of
the regulations, SENASA must confirm that the fruit was produced in
accordance with the requirements of the regulations; the grove and
buffer area sanitation measures are one of those requirements. SENASA
will keep records regarding its inspection of each export grove and
buffer area, and APHIS may request to review those records. Further, as
noted previously in this final rule, the operational work plan
governing the administration of the export program will provide for the
active and direct monitoring of the export program by APHIS personnel;
that monitoring will include verification of the required grove
sanitation measures.
Comment: The risk assessment states that groves are inspected for
disease symptoms prior to fungicide applications, and fruit with
possible disease symptoms is sent to a laboratory for analysis. The
timing of fungicide applications is determined by ``an expert system.''
In section 8.f. P1 of the risk assessment, it indicates that the export
groves would have a ``minimum of two or three additional applications''
of fungicide, as opposed to the total of at least two specified in
section 8.a. of the risk assessment and in the proposed rule. The
proposed rule states that SENASA will determine timing of fungicide
applications ``during the growing season,'' based on monitoring of
climatic data, fruit susceptibility, and the presence of disease
inoculum, and will monitor for correct fungicide application. There is
no requirement in the proposed rule for inspection of the groves for
pests at times of fungicide application, nor for laboratory analysis of
suspect fruit at this time (if there is any fruit at the times of spray
application). There is no discussion of what is meant by ``presence of
disease inoculum.'' There is no requirement that the fungicide
treatment include any fruit, leaves, or branches on the ground that
have not been removed. It is not required by the proposed rule that
SENASA use an expert system to determine fungicide application times.
Response: After the risk assessment was prepared, and before the
provisions that formed the basis of the proposed rule were fully
developed, SENASA suggested that the inspections be conducted after the
fungicide treatments, when there is a better chance of detecting the
disease; this accounts for the difference between the risk assessment
(which speaks to inspection before fungicide treatment) and the
proposed rule on this subject. The oil-copper-oxychloride treatments
will be applied during the period of greatest susceptibility of the
fruit to infection (i.e., from the time that three quarters of the
petals have fallen to the time the fruit have reach 3 cm in diameter).
Given that disease symptoms are unlikely to be manifested at that stage
of fruit development, the proposed rule did not, and this final rule
does not, call for inspections prior to the application of those
treatments or the laboratory inspection of suspect fruit at that time.
With regard to the number of oil-copper-oxychloride applications,
section 8.f P1 of the risk assessment did, as noted by the commenter,
state that groves would receive ``a minimum of two or three additional
applications of fungicide,'' while elsewhere in the risk assessment and
in the proposed rule the number of applications was characterized as
``two or more'' and ``at least twice.'' However, the way in which the
number of applications was characterized did not have any effect on our
estimation of the mitigation value of the fungicidal sprays. Our
estimates were not based on any finite, predetermined number of sprays;
rather, the risk assessment assumed that the timing and number of
sprays would be determined using SENASA's expert system, with the
optimal number of sprays being applied to prevent infection.
With regard to the term ``expert system,'' which was used in the
risk assessment, we chose to describe the components of the system in
the proposed rule (i.e., monitoring of climatic data, fruit
susceptibility, and the presence of disease inoculum) rather than
simply use the term itself. The risk assessment and the proposed rule
are, therefore, referring to the same thing. We have included the term
``expert
[[Page 37623]]
system'' in Sec. 319.56-2f(b)(5) of this final rule to make that clear.
With regard to what is meant by ``presence of disease inoculum,''
SENASA's monitoring of the presence of disease inoculum considers both
the presence of fallen leaves within the grove, as leaves have been
identified as the primary source of inoculum, as well as the incidence
of disease in the area surrounding each grove.
We did not include provisions for the spraying of fruit, leaves, or
branches that may be on the ground because the oil-copper-oxychloride
treatment is intended to prevent infection in the developing fruit
itself and because the required grove sanitation measures are intended
to leave the ground in the grove free of such debris.
Comment: Eureka-type lemons, which are commonly planted in
Argentina, do not have a very distinct start and finish of flowering,
depending on climatic conditions. Under mild winter conditions,
flowering can occur year round; indeed, some reports indicate that
lemons are harvested year round in Tucuman province. In one report,
Argentine researchers observed both immature and mature lemons on the
sampled trees at the same time in Salta and noted that the presence of
different aged fruit provides for an additional risk of fruit
infection. How can a grove be certified as having been cleaned prior to
bloom when bloom is not specifically seasonal?
Response: While there may be multiple blooms in a year under mild
winter conditions, Argentina reports that there is, as occurs in the
United States, a main spring flush during which most of the trees will
bloom, and it is the fruit from those trees that will be exported to
the United States. Therefore, the blossoming period in the Argentine
production areas is distinct enough to allow for the cleaning and
inspection of the groves and buffer areas prior to blossom.
Comment: The timing of flowering in not necessarily distinct in
some common lemon varieties, and it is not clear how the timing of the
oil-copper-oxychloride treatments will be determined when flowering and
fruit set occur over several months. The efficacy studies of the
fungicide treatments need to provide for careful testing of timing of
the treatments to deal with the different bloom lengths, fruit set,
rainfall patterns, and disease incidence in the different citrus
species and the different regions.
Response: The timing of each treatment application will be
determined by SENASA using an expert system that considers climatic
data (including temperature and rainfall patterns), fruit
susceptibility (which is dictated in part by the timing and length of
bloom, when fruit set occurred, and the relative disease susceptibility
of each species), and the presence of disease inoculum (which takes
into account both the presence of fallen leaves within the grove, as
leaves have been identified as the primary source of inoculum, and the
incidence of disease in the area surrounding each grove). The goal of
the expert system is to maximize the effectiveness of the oil-copper-
oxychloride treatments in preventing the fruit from becoming infected.
Whether or not that goal has been met will become apparent during the
laboratory incubation and examination of the 20-day preharvest sample,
as well as through the grove and packinghouse inspections.
Comment: The proposed rule fails to require that certified groves
keep detailed records of the various blooms and required program steps
(e.g., when the spraying and debris-clearing programs are carried out).
Any program which APHIS develops should be subject to further public
comment.
Response: There is no need for APHIS to develop a recordkeeping
program as suggested by the commenter. As stated in the proposed rule
and in this final rule, SENASA is responsible for inspecting the
registered groves prior to blossom to ensure that the required
sanitation measures have been accomplished, as well as for determining
the timing of the oil-copper-oxychloride treatments and monitoring
their application. SENASA will maintain records of these activities as
part of its citrus fruit export program, and will make those records
available to APHIS during program reviews or when otherwise necessary.
Comment: From the APHIS-SENASA correspondence, it is clear that
APHIS had wanted an inspection of the orchard prior to the fungicide
treatments. However, SENASA requested that the inspection for disease
occur after the treatments. APHIS must explain its reasoning for why
the inspection of a grove for disease before fungicide applications was
not included in the proposed rule.
Response: Until the fruit has matured somewhat and has begun to
color, the symptoms of citrus black spot will not be apparent. Since
the fruit would be too small and would not have colored yet prior to
the fungicide applications, we concurred with SENASA's suggestion that
the inspections be conducted after the treatments, when there is a
better chance of detecting the disease.
Comment: No specific rate for the copper oxychloride sprays is
provided in the proposed rule. It appears that the Argentine
researchers found that a rate of 0.36 percent was more effective in
preventing the disease, but SENASA has stated that a rate of 0.18
percent would be used for the export program, which may be ineffective
at least some of the time or on some fruit, according to the
information in the record. APHIS should determine why the lower copper
oxychloride rate was chosen by SENASA, even though the data showed the
higher rate to be more effective.
Response: The lower oil-copper-oxychloride application rate was
recommended by SENASA based on its studies that showed that the 0.36
and 0.18 percent application rates were both effective in preventing
disease in test plots when the disease was evident in the control
plots. Given that the 0.18 percent application rate was shown to be
effective in preventing disease, and given that this rule requires at
least two applications of the fungicide during the growing season, we
have accepted SENASA's recommendation that the 0.18 percent application
rate be used.
Comment: It appears that Argentine researchers performed only one
test to assess the effectiveness of the in-season fungicide treatments
for sweet orange scab and that only one test was conducted using both
in-season fungicide treatments and post-harvest chemical treatments.
This limited testing is not sufficient to determine the effectiveness
of the proposed measures. APHIS should provide or cite efficacy data
for the proposed copper oxychloride sprays on the incidence of sweet
orange scab.
Response: The American Phytopathological Society's Citrus
Compendium (Whiteside et al., 1988), which was cited in the body of the
risk assessment (p. 57) and in the pest data sheet for sweet orange
scab (p. 101), indicates that copper sprays are effective protectants
to prevent the infection of susceptible fruit by sweet orange scab.
Comment: While the risk that sweet orange scab might be introduced
into the United States may be reduced by timely, reliable, and negative
surveys, there are still some unresolved taxonomic issues surrounding
the Elsinoe species complex. The less than distinct differentiation
between possible strains/biotypes strongly suggests that additional
systematic research is needed to fully understand this pest complex.
Response: While there may be room for additional systematic
research in order to fully differentiate between possible strains/
biotypes of Elsinoe spp.,
robop...@us.govnews.org
Posting-number: Volume 65, Issue 116, Page 37607, Part 1
[[Page 37640]]
that additional detail can necessarily be equated with greater
accuracy. In the case of this particular risk assessment--and virtually
any plant pest risk assessment--separating variability from other forms
of uncertainty would constitute overinterpretation of available data.
Comment: The risk assessment states that all the distributions are
based on the professional judgment of the team of entomologists who
developed the risk assessment. That professional judgment appears to
have been based on research or actual data in only a few instances.
APHIS certainly must have access to data from inspections and from
previous infestations of pests in the United States. The use of such
data would result in much more credible distributions than those
derived solely from professional judgment. It is possible, even likely,
that distributions based solely on professional judgment (i.e., without
reliance on data) are wildly inaccurate, placing the reliability of the
analysis in serious question.
Response: We did indeed use those data whenever they were
available, and they were cited in several locations (e.g., Alfieri et
al., 1994; Brown et al., 1988; Gould, 1995; etc.). The distributions
were not based solely on professional judgment, i.e., ``without
reliance on data'' as suggested by the commenter. But for many of the
nodes, no direct data existed to provide estimates for the input
distributions, and professional judgment informed by the ``indirect''
sources of information available (e.g., scientific literature regarding
a particular pest, interception records, etc.) was used according to
international standards and accepted practice.
Comment: In no case does APHIS discuss the decision criteria used
to select the type of probability distribution (normal, lognormal,
beta), let alone why only these three particular distribution types
were used. In most cases (such as in the construction of distributions
for fruit fly and citrus canker incidence, the probability that a pest
is detected at harvest, the probability that the pest is detected in
the packinghouse, the probability that the pest survives shipment,
etc.), no justification beyond ``expert judgment'' is given for the
parameters selected to characterize the distributions. While we
recognize that extensive data originally may not have been available to
characterize, such deficiencies should have been recognized very early
in the process and further studies carried out to fill in the gaps in
data.
Response: In addition to the three distribution types identified by
the commenter, we also estimated several nodes using another type of
probability distribution, truncated lognormal. Distributions were
chosen to reflect the current state of scientific knowledge. We
explained the nature of each distribution chosen; in fact, we provide a
separate section for each distribution. The explanations can be found
in section 8.e., with titled subparts for each node (probability
distribution) used for the fruit fly simulation, and section 8.f., with
titled subparts for each probability distribution used for the three
diseases. We provided justification for our choice of distribution in
many, but not all, cases. For example, in the discussion of the choice
of distribution to represent the likelihood that fruit fly larvae will
survive post-harvest treatment (section 8.e P5) we state:
Treatment schedules were based on demonstrated efficacy of
probit 9 (99.9968 percent) mortality. This corresponds to a survival
rate of 0.00003 (0.003 percent). We represented survival as a
lognormal distribution with a mean of 0.0001 and a standard
deviation (sd) of 0.00011. A sd of 0.00011 was chosen because the
resulting distribution has a mode (peak of the distribution) at
0.00003.
In this case, although we did not offer a discussion of why a
lognormal distribution was used, since ``there is a significant body of
work that shows a particular family of distributions to match the
variability in the type of variable in question'' (D. Vose, in press),
insect response to treatments such as this is distributed lognormally.
The statistical procedure (probit analysis) that led to the probit 9
estimate (referred to above and in the risk assessment) is based on the
assumption that response is distributed lognormally. This phenomenon
and the lognormal distribution lies at the heart of this branch of
science and is documented in the scientific references provided in the
risk assessment. Additional information regarding the selection of
distribution types, including those not discussed in detail in the risk
assessment, is contained in the addendum to the risk assessment that is
available from the person listed under FOR FURTHER INFORMATION CONTACT.
Comment: Some justification needs to be provided for the estimates
in the risk assessment for situations in which some data are available.
For example, APHIS acknowledges that field and laboratory research has
been performed on fruit fly infestations in commercial citrus
production, yet it does not specify how (or even if) this research was
used to derive the fruit fly infestation distribution, beyond stating
that the entomologists working on the risk assessment used their
professional judgment. Neither risk assessment nor the rulemaking
record contains any documentation of either the evidence used or the
methodology used to codify that evidence as probability distributions.
Response: Our knowledge of each of the insect pests and diseases,
which, given the lack of directly applicable data in many cases, played
an important role in the formulation of our estimates, is summarized in
the pest data sheets contained in the risk assessment's appendices, and
our sources of information are cited in each pest data sheet and in
section III (References) of the risk assessment. Where direct
information was available, that information was identified; the same
holds true for the use of expert judgment in arriving at our estimates.
The addendum to the risk assessment that is available from the person
listed under FOR FURTHER INFORMATION CONTACT identifies, for each node,
the direct information and expert information that was available and
provides a discussion of how the available information was used in the
construction of the distribution.
With regard to the commenter's specific example, we had no direct
evidence of what the past, present, or future fruit fly infestation
levels may be in Argentina. But regardless of where citrus is produced,
we are confident that our distribution, which was based on expert
judgment informed by experience with fruit flies and by information
gleaned from numerous cited sources, reflects the entire realm of
possibilities. As stated in section 8.e P1 of the risk assessment:
The minimum infestation rate used in the calculations was
0.000535 (e.g., one infested lemon per 280,400 lemons). The maximum
infestation rate sampled for calculations was 0.495 (e.g., half of
all boxes or one infested grapefruit per every 100 grapefruit).
Thus, because of our uncertainty, we used a distribution providing
values representing infestation levels from where the pest is nearly
nonexistent (one lemon out of 280,400) to an infestation level that
would stop production (half of all boxes infested).
Comment: The number of boxes of fruit that will be shipped to the
United States from Argentina is estimated as 1.2 million 18-kg boxes of
fruit per year. This information was provided by citrus industry
representatives in Argentina. From this single piece of data, APHIS
constructed a normal distribution with a mean of 1.2 million and a
standard deviation of 200,000 to represent the frequency of citrus
shipments each year. APHIS states that this distribution was
[[Page 37641]]
constructed to allow for variation in the frequency of shipments that
might result from variations in production, the frequency of shipments
cleared for export, and market demands in the United States. Quite
apart from the question as to whether a year-to-year variability is the
correct statistic to evaluate in this context, APHIS does not specify
how it arrived at a standard deviation of 200,000--APHIS presents no
evidence whatsoever, nor provides any methodology. It is certainly
possible to provide a plausible methodology for obtaining some value
for variability; for example, basing it on distributions for the U.S.
importation of citrus fruit from other countries, or on distributions
for other exports from Argentina, or even citrus exports to countries
other than the United States. Moreover, this annual variability may not
be required, and should certainly not be used in the risk assessment as
APHIS has used it.
Response: While it is true that this situation could have been
analyzed in greater detail, conducting the suggested analysis would
represent overinterpretation of available data. We believe that the
suggested analysis would obscure the situation, provide a false sense
of security, and probably lead to a less accurate estimate.
In constructing this distribution, the expert group started with
the point estimate of 1,200,000 boxes per year supplied by Argentina;
the group then considered whether it was reasonable to assume central
tendency. The group agreed that the point estimate from Argentina was
the best available estimate, but that values both above and below
1,200,000 were possible (i.e., the distribution should demonstrate
central tendency around 1,200,000). The group discussed a variety of
factors that could affect the number of boxes imported, e.g., variation
in harvest, variation in U.S. demand, unanticipated costs of the export
program leading to less interest by growers, unanticipated success from
the exporters' point of view leading to greater interest by growers,
etc. There were, however, no data available that would allow us to
estimate the effects these factors would have on the number of boxes
shipped. Thus, the standard deviation of 200,000 chosen by the expert
group represents uncertainty and not, as the commenter suggests,
variability per se, in the model. (As noted in a recent paper published
in the journal Risk Analysis (Gray et al., 1998), ``[k]nowledge of
variability must be based on empirical estimates, otherwise it is
another source of uncertainty.'')
With no information suggesting any particular distribution type,
the group believed that a normal distribution was most reasonable
(i.e., symmetrical uncertainty around the mean/mode/median). They
agreed that although the actual number of boxes imported would almost
certainly be other than exactly 1,200,000 per year, they had no
legitimate reason to believe it would be higher as opposed to lower or
vice versa, or what the year-to-year variability would be. Using the
software package Risk View <SUP>TM</SUP> (Palisade Corp., Newfield, NY)
and trial and error, the group specified the (standard deviation) value
that provided what they considered to be appropriate positions for the
5th and 95th percentile values in the distribution.
Comment: In section 8.f. P1 of the risk assessment, APHIS
identifies data for sweet orange scab and citrus black spot infection
rates in Argentina. It claims that limited field surveys indicate that
39 percent of sampled trees in control plots (untreated) bear fruit
with evidence of sweet orange scab. The distribution constructed by
APHIS for sweet orange scab infection is a beta distribution with a
mean probability of 0.5 that a box of produce is infected. How is
APHIS's distribution related to the infection rates in field surveys?
Why does APHIS select a beta distribution to characterize this
probability? How does APHIS arrive at the two parameters necessary to
characterize the beta distribution? There is no information in the risk
assessment or the rulemaking record to support the constructed
distributions. Similarly, APHIS cites the results of field surveys for
citrus black spot as finding 14 percent and 82 percent of sampled fruit
infected with citrus black spot in 1994 and 1995, and 56 percent of
sampled trees infected in 1996. APHIS goes on to say, ``Our expert
information predicted that the incidence of citrus black spot, on a per
box basis, in untreated groves would range from a minimum of 10 percent
to a maximum of 100 percent with a most likely value of 50 percent.''
APHIS then proceeds to construct a beta distribution with a mean of 60
percent and a mode (most likely value) of 67 percent. Again, there is
no information in the rulemaking record or the risk assessment to
indicate how this distribution incorporates either the results of the
field surveys or the expert information.
Response: As stated in the risk assessment document, ``our
estimates * * * were based on limited field survey data provided by
Argentina and expert information provided by scientists familiar with
citrus production in Argentina and/or the pathogen.'' Because the field
survey data were limited, our expert estimates of these probabilities,
which were informed by the body of scientific knowledge cited in the
references and summarized in the pest data sheets, reflected what we
considered appropriate levels of uncertainty, and the distributions
were derived to reflect those estimates.
The experts relied on professional judgment to construct
probability density functions that accurately represented their
understanding of the available information. For both citrus black spot
and sweet orange scab, the experts, after discussing available
scientific and other information, identified the general shape of the
distributions that were needed to account for all identified or assumed
variation and uncertainty. In both cases, the experts agreed on a beta
distribution, and discussions ensued to establish the parameters of the
chosen distributions. The experts used an iterative process in
conjunction with the software program Risk View <SUP>TM</SUP> (Palisade
Corp., Newfield, NY) to provide instant feedback on the shape and
statistics associated with any particular set of parameters. This was
largely trial and error, and the experts succeeded in producing beta
distributions that represented the group's understanding of the
available information. The experts used a consensus approach. The
distributions captured the full range of variability and uncertainty
considered essential by all experts, even though they may have
represented more uncertainty than was felt necessary by any single
expert.
Comment: The rulemaking record contains some information on the
field surveys performed in Argentina, in the form of a very short
summary of some results of those field surveys. However, the record
omits crucial information required to interpret these summary results,
including the protocols used for the field surveys; complete, written
scientific documents describing the surveys and their results; and the
contemporaneous field notes that should have been taken during the
surveys. Despite this lack of information, we believe that APHIS'
interpretation of the results is incorrect, as applied in its risk
assessment. Adding up the results of the 1996 field results, in which 5
fruit per tree were sampled from each of 300 randomly selected trees,
gives:
[[Page 37642]]
------------------------------------------------------------------------
Number of trees (out of 300 in each case)
Number of infected -----------------------------------------------
fruit per tree Sweet orange scab in Citrus black spot in
oranges lemons
------------------------------------------------------------------------
0 181 133
1 95 78
2 22 46
3 2 25
4 0 15
5 0 3
------------------------------------------------------------------------
(For this analysis, we do not distinguish Elsinoe australis from
Elsinoe fawcettii.)
The incidence of infection (per fruit) was 9.67 percent for sweet
orange scab in oranges and 21.3 percent for citrus black spot in
lemons. APHIS apparently took the fraction of trees infected to be
equal to the number of trees with observed infected fruit divided by
the total number of trees (119/300=39.7 percent for sweet orange scab
in oranges, 167/300=55.7 percent for citrus black spot in lemons). This
is incorrect, however, since not all fruit on each tree were examined.
It is clear that not all fruit are infected even on an infected tree,
so sampling 5 fruit per tree will likely yield zero fruit infected from
quite a few infected trees.
A simple approach to analyzing these experimental data is to assume
some probability for a tree to be infected, and then to assume that all
the fruit on an infected tree have an equal probability for infection
(while those on uninfected trees have zero probability for infection).
For sweet orange scab in oranges, this leads to a best estimate for the
fraction of trees infected of 97.7 percent, and the observations are
entirely consistent with (and statistically indistinguishable from) 100
percent infection. In that case, with 9.67 percent fruit infected, we
would expect to see almost exactly the pattern of detections (per tree)
actually observed (it is just a binomial distribution of infections).
For citrus black spot in lemons, the best estimate for the fraction of
trees infected is about 64 percent, with 33 percent of the fruit
infected on an infected tree (note that 0.64 x 0.33=0.21, the
observed fraction of fruit infected), using the same simple model.
The simple model used here leads to binomial statistics, although
it is clear in the case of citrus black spot that there is actually
more variability than the binomial distribution would predict. It is
not difficult to postulate a more plausible model with the higher
variability expected because of differences between geographic areas,
groves, or field conditions. Accurate evaluation of the variability
requires more field data, and is required for an adequate scientific
evaluation of the Argentine situation.
Response: We acknowledged that the information we initially
provided to this commenter did not reflect the entire body of data that
was used to support the proposed rule. However, as we also noted, we
did forward additional documentation to the commenter following the
close of the comment period in response to the commenter's FOIA
request. We understand that the commenter is reviewing that additional
documentation, and we have stated our willingness to thoroughly
consider, and address as appropriate, any new scientific information
that comes to light as a result of that review that has a material and
significant bearing on this rulemaking proceeding.
With regard to the commenter's argument that APHIS' interpretation
of the results was incorrect, there are several ways to interpret and
use the data presented by the commenter to support his argument.
However, we believe that the analysis suggested by the commenter is
based on invalid assumptions. Specifically, although it would be
inadvisable to ``assume some probability for a tree to be infected,''
it would be a critical error ``to assume that all the fruit on an
infected tree have an equal probability for infection''; this is known
to be false. That is why the five fruit were sampled from the area of
the trees where infected fruit were most likely. It would also be an
error to assume that on trees where none of the five sampled fruit were
infected, all fruit were not infected. With a sample of five fruit, it
was known that not all infected trees were identified. That is one of
the reasons why even though infected fruit were found on only 39.7
percent of the sampled trees, the mode and mean of our estimate (input
distribution) was higher (50 percent). The commenter also does not
account for the fact that our risk unit was a box of fruit, not an
individual fruit or entire tree. This is discussed further in the
response to the next comment.
Comment: From the description in section 8.f P1 of the risk
assessment, APHIS appears to believe that the fraction of boxes
infected is in some simple way related to the fraction of trees
infected, since the only discussion of the former immediately follows
the estimate of the latter in such a way as to suggest such a
connection. There is no other discussion in either the risk assessment
or the rulemaking record, and the values adopted by APHIS are very
similar. This is incorrect however. The final shipping boxes are not
filled from individual trees, but in the packinghouse after processes
that will substantially mix fruit from multiple trees. To a good
approximation, fruit will be randomized during harvesting, storage, and
the packing process, so that a given box will be packed with fruit from
a random selection of trees. For sweet orange scab in oranges, the
probability for no fruit in a box to be infected would thus be about
(1-0.0967)<SUP>100</SUP> for 100 fruit per box, or 3.8 x
10<SUP>-5</SUP> if the structure of APHIS's model were correct. That
is, the probability for an infected box of oranges (i.e., a box
containing one or more infected fruit) in the base case for sweet
orange scab is about 99.9962 percent. For citrus black spot in lemons,
a similar calculation shows that the probability for a box of lemons
(150 per box) to be infected in the base case is about 1-2.5 x 10-16,
which is 100 percent for all practical purposes, under the same
assumptions. In fact, the structure of APHIS's model is not correct, so
these calculations are somewhat awry. One cannot follow a ``box'' of
fruit through from harvest to packing, since the box is not constructed
until after many processes that operate on individual fruit
(independent of which box they finally end up in) and may affect the
probability of infection. Thus estimating probabilities ``per box'' at
this stage is itself a futile exercise. A better approach is to
evaluate on a ``per fruit'' basis throughout the risk assessment.
Response: The commenter states that it is incorrect to believe that
the fraction of boxes infected is in some simple way related to the
fraction of trees infected. We agree that there is no way to go
directly from a sample of trees (with a sample of fruit taken from each
tree) to either a per-fruit or per-box estimate. However, we believe
that the sample, which is indicative of the overall infection rate in
the grove for the year in which the sample was taken, can be used as a
starting point for an estimate of the per-box infection rate. That
being said, our estimates were made with the knowledge that factors
existed that argued for both (1) a lower per-box infection rate (i.e.,
not all fruit on a tree with infected fruit are infected) and (2) a
higher grove infection rate (i.e., not all sampled trees with infected
fruit tested positive). This is one of the reasons that even though
sweet orange scab-infected fruit were found on 39.7 percent of the
sampled trees, the mode and mean of our estimate was higher (50
percent).
As stated in the risk assessment, ``Our expert information
predicted disease incidence, on a per box basis, to range from a
minimum of 1 percent to a maximum of 90 percent with a most likely
value of 50 percent.'' However, because of the uncertainty in the
[[Page 37643]]
information, and because of the uncertainty of the experts regarding
the per-box infection rate, we specified a distribution that allowed
values for infection rates across the entire range of probabilities
from 0 through 1 (100 percent). For sweet orange scab, we characterized
our baseline estimate for the likelihood harvested fruit was infected
(P1) with a beta (3.5, 3.5) distribution (see Table 8 of the risk
assessment). With this distribution, although the most likely value was
50 percent, values up to and including 100 percent were possible. The
maximum value actually used for calculations was 0.9773+, i.e., 97.7
percent. We made our estimates according to international guidelines
for plant pest risk assessments, which have been endorsed by the United
States, and are consistent with common practice in risk assessment as
reported by Hoffman and Kaplan (1999, see reference above). We used
available data and professional judgment to represent the data in the
terms needed for the risk assessment.
With regard to our use of ``per-box'' probabilities, we have stated
previously in this document that we believe that our selection of the
box, rather than individual fruit, as the risk unit is appropriate.
Once the fruit are packed, they are no longer independent of each
other, and it is boxes, and not individual fruit, that will be
shipped--to and, in all likelihood, remain in--specific destinations in
the United States. Even though no one unit is perfect for each node, we
decided that it would be most transparent, defensible, and correct to
use a consistent risk unit throughout the model. The primary problem
perceived with using individual fruit as the risk unit was the
different size of the various fruit being considered (i.e., lemons,
oranges, and grapefruit). Separate modeling for each type of fruit
would have complicated the assessment significantly and needlessly; the
expert group did not believe that separate modeling would improve the
accuracy of the risk estimates, especially given the inherent
uncertainties in the input parameters.
Comment: For citrus black spot, some additional data are available
from the earlier small field experiments described in the rulemaking
record. However, these were not field surveys as claimed by APHIS in
the risk assessment (for example, the sampled trees were not selected
at random), but rather the control side of experiments apparently
designed to examine the effectiveness of fungicides; again no
protocols, scientific documentation, field notes, or analyses are
included in the rulemaking record. These small samples showed incidence
per fruit of 0/432, 0/432 and 41/216 (19 percent) for grapefruit, and
36/252 (14 percent) and 207/252 (82 percent) for oranges. The first and
last pairs of these samples were from the same plot in different years.
The APHIS characterization of these surveys in the risk assessment
omitted entirely the results in grapefruit. The results, although not
field surveys, do illustrate the possibility of no observed infection
even without fungicidal treatments, and the high variability from place
to place and year to year.
Response: As noted by the commenter, the data we used were obtained
through experiments using treated and untreated control plots. It is
also the case that the risk assessment did not explicitly cite the
grapefruit data reviewed by the commenter (which is available in the
additional documentation that may be obtained from the person listed
under FOR FURTHER INFORMATION CONTACT). That being said, it is clear
from the available information that citrus black spot, as is the case
with many diseases, is more prevalent in some years than in others. For
this reason it is entirely possible that in some years no infection
would be observed even if fungicides were not applied. The disease can
be variable from place to place and year to year. This fact is not
relevant to the efficacy of the systems approach, which is designed to
mitigate the risk during years in which disease is likely.
Comment: In the risk assessment, APHIS makes estimates for the
probability of infection when the mitigation measures are taken. There
is some confusion over the precise meaning assigned to the various
mitigation measures that may substantially affect infection
probabilities. Although APHIS does not provide any indication of its
approach (either citation or methodology) for estimating post-
mitigation infection probabilities, simple analyses of the Argentine
data on citrus black spot suppression by copper oxychloride treatment
are possible, as shown in the following example.
In those experiments, assume that the probability for a control
(untreated) fruit to be infected is p (different in each experiment and
from season to season), and that treatment with one application of
copper oxychloride multiplies that probability by a factor R (different
for each treatment type, and hopefully less than unity, to have an
effective treatment), with two applications reducing it by
R<INF>2</INF> (one could, and should, test this latter assumption).
Assume binomial responses (e.g., because all fruit are equally likely
to be infected, and treatment is equally effective on all fruit), and
use binomial likelihood methods. We can then estimate p and R from the
available data, together with the uncertainty on R, if desired. For
grapefruit, two of the three available experiments show no responses at
all, so they are useless for estimation of R. For oranges, we could
test whether two applications really reduced the incidence equally in
each application; inspection of the data shows that this is certainly
plausible.
Applying this simple model to the single useful experiment on
grapefruit gives a maximum likelihood estimate (MLE) for R of 1.15 for
the 1.8 percent treatment, and 0.31 for the 3.6 percent treatment. Thus
two applications of 3.6 percent might reduce the rate 10-fold and three
applications 33-fold. However, the uncertainty is large. This
experiment shows no effect of the 1.8 percent treatment.
For oranges, the MLE for R is 0.22 for 1.8 percent and 0.20 for 3.6
percent, so that two applications of 3.6 percent might reduce the
infection rate 24-fold, and three applications 118-fold. Notice that a
24-fold reduction from the control group rate of 36/252 is entirely
consistent with the observed 0/252 in the 93-94 season when two
applications were made.
Such analyses could be extended in various ways. For example, in
this model the R values for 1.8 percent are significantly different for
grapefruit and oranges, but for 3.6 percent they are not significantly
different. The MLE for the combined value (for 3.6 percent) is 0.25, so
that the model prediction for two applications is a 16-fold reduction
in disease rate, and for three applications a 128-fold reduction. With
so few experiments, and none available for analysis with three
applications (versus one and two), one cannot test the model hypothesis
that each application simply reduces the disease rate by a similar
amount. Apparently, more experiments were in fact performed, but the
rulemaking record reports only summary results that cannot be
interpreted without much more information.
This analysis indicates the paucity of the data available in the
rulemaking record. For grapefruit, the one available experiment on the
effectiveness on citrus black spot of 1.8 percent copper oxychloride
treatment shows it to be ineffective, although it is almost as
effective as 3.6 percent on citrus black spot on oranges.
Response: The commenter offers an alternative way to consider the
estimated efficacy of mitigation
[[Page 37644]]
treatments. However, the approach is complex and highly speculative,
and in our estimation represents an overinterpretation of available
data, which, as the commenter notes and we acknowledged in the risk
assessment, were limited. Copper oxychloride is a well established
treatment for citrus black spot and sweet orange scab. Our estimates
concerning the efficacy of these mitigation treatments are based on
expert interpretation of results that have been obtained in a variety
of studies on the control of these diseases (for example, as referenced
in Whiteside et al., 1988, as cited in the risk assessment).
Comment: Only one experiment reported in the rulemaking record
addresses the effectiveness of copper oxychloride treatment on citrus
black spot in lemons. While it apparently showed that the treatment was
effective, there were no details on the protocols adopted
(concentrations, number of applications, experimental procedures, and
so forth), although a naive calculation indicates that the incidence
was reduced more than 100-fold (approximately 95 percent confidence
limit). In another document there are two figures labeled ``Chemical
control (Santa Clara-Jujuy),'' apparently for treatments in the 1993-94
and 1994-95 seasons, that appear to correspond to suppression of citrus
black spot in Eureka lemons, but there is no explanation of the origin
of the data used in those two figures. APHIS should identify which
treatments were applied in the tested groves and describe the level of
disease in the region near the tested groves. Similarly, the
effectiveness of copper oxychloride treatment for sweet orange scab is
only demonstrated in one experiment (on oranges) in the rulemaking
record, but the experimental protocols are not reported (number of
treatments, concentrations, application rates, experimental procedures,
and so forth). It is possible that some of this mitigating effect may
be due to other simultaneous measures, such as cleaning of the orchard
floors; however, in the absence of experimental protocols, this cannot
be determined. Moreover, the available evidence is insufficient to
adequately characterize that effect. For a defensible estimate of the
effect of copper oxychloride treatments on citrus black spot and sweet
orange scab, APHIS must have experimental data demonstrating its
effectiveness under varying conditions, in different areas, and for
different fruit. Furthermore, APHIS must provide details of its
analyses demonstrating effectiveness, and must show the connection
between the experimental data and the distribution used in the risk
assessment.
Response: As we have recognized in numerous instances in this
document, there is not always a one-to-one correlation between the
experimental data, which is limited in some cases, and the
distributions used in the risk assessment. In this case, our estimates
on the effectiveness of the copper oxychloride treatment, which is the
treatment that was applied in the tested groves, are derived not solely
from evidence supplied by Argentina but also from reports in the
scientific literature (e.g., as reported by Whiteside et al., 1988,
cited in the risk assessment). These reports represent results that
demonstrate the effectiveness of copper oxychloride in reducing disease
incidence under varying conditions, in different areas, and for
different fruit, even in areas where the level of disease is high.
Comment: The risk assessment (8.f. P4) states that it is assumed in
the baseline that the fruit ``treatments may include, but are not
limited to, washing fruit in a detergent bath, waxing and fungicide
dips.'' It is not clear how much more extensive the proposed treatment
program is, since the proposed treatment program could be described in
exactly the same fashion as the baseline (although washing in detergent
is not prescribed). The risk assessment (8.f. P4) also states that
``the only post-harvest treatment for pathogens that is specifically
prescribed in the proposed export program is a fruit dip in 200 ppm
sodium hypochlorite (bleach) for 2 minutes.'' Actually, the preamble
and proposed rule prescribe other specific treatments (immersion in
orthophenilphenate of sodium, spray with imidazole, and application of
2-4 thiazalil benzimidazole and wax) that are specifically for
treatment for pathogens (although this may depend on one's definition
of ``pathogen'' in this context).
Response: The fact that the proposed treatment program examined in
the risk assessment did not take into account the other specific
treatments (immersion in orthophenilphenate of sodium, spray with
imidazole, and application of 2-4 thiazalil benzimidazole and wax) that
were described in the proposed rule and required by this rule can be
attributed to the fact that the risk assessment was completed before
the proposed rule was fully developed. However, it is clear that
considering those treatments in the mitigated scenario in section 8.f.
P4 of the risk assessment would have resulted in a higher risk
reduction rating for the post-harvest mitigations, thus lowering the
overall risk, which we already considered to be very low.
Comment: APHIS's assumptions that sweet orange scab-infected fruit
is removed with 89 percent probability at harvest (mean value for both
baseline and mitigation program), while citrus black spot-infected
fruit is removed at harvest with mean 50 percent probability (baseline)
and 89 percent probability (mitigation program), cannot be supported by
any available evidence. We see three problems with this assumption:
<bullet> The incidence data used to support this are largely, if
not totally, post-harvest incidences for latent disease, not field-
apparent incidence of disease in unharvested fruit. Any probability for
detection during harvesting is apparently already incorporated in such
values.
<bullet> APHIS has assumed that pickers in Argentina make an
attempt to cull blemished/diseased fruit, but our information indicates
that pickers in Argentina do not cull fruit; rather all picked fruit is
sent to the packinghouse for sorting there.
The entire object of chemical and other treatment is suppression of
disease. The disease infections in the export groves should be latent
at the time of picking, as evidenced by the data provided by the
Argentines, so that there is no visible evidence of disease in
harvested fruit. It should therefore be physically impossible for the
pickers to detect latent disease.
With a reduced incidence at harvest, in the case of citrus black
spot probably of entirely latent infections, there is no evidence that
infected fruit is more likely to be removed by harvesters. At minimum,
APHIS needs to document harvesting practices and obtain experimental
evidence for removal probabilities at harvest. Such experiments would
be very straightforward, since they simply involve random sampling of
unharvested trees followed by sampling of fruit harvested in the normal
course of events (and preferably also of the fruit, if any, that is
culled by the harvesters). These should have been incorporated in
experimental protocols at an early stage of experiment planning.
Response: The commenter states that we used incidence data to
support our estimates regarding the removal of diseased fruit in P2,
``Pathogen not detected at harvest.'' This statement is incorrect.
While data on disease incidence did affect our estimates for the
likelihood that fruit are diseased in P1, ``Harvested fruit is
infected,'' we indicated in the risk assessment (section 8.f P2, p.36-
38) that our estimates for P2
[[Page 37645]]
were based on a variety of factors, including ``the nature of the
disease symptoms, the skill of the picker in recognizing diseased fruit
and the quality standards employed by a given grove in culling diseased
fruit.'' Because sweet orange scab symptoms are easily seen during
harvest, our estimates were based on a higher (compared to citrus black
spot) degree of confidence that sweet orange scab-infected fruit will
be identified and removed at harvest. The commenter also states that
the ``entire object of chemical and other treatment is suppression of
disease.'' This statement, which we understand to be referring to
citrus black spot, is also incorrect. As we have stated elsewhere, the
object of the field treatments is the prevention of the disease, and
not merely the suppression of symptoms. Latent infections of citrus
black spot would not be observed, which is why our baseline estimate
that this disease will be missed is higher. However, the systems
approach will reduce the likelihood of latent infections, thus
decreasing the likelihood that diseased fruit will be missed.
Comment: APHIS provides estimates for the probability of detection
of sweet orange scab and citrus black spot at packinghouse inspection.
Again, no evidence is provided to support its estimates of 82 percent
(mean: baseline) and 95 percent (mean: mitigation program) probability
of detection of sweet orange scab, or with 74 percent (mean: baseline)
and 95 percent (mean: mitigation program) probability of detection of
citrus black spot. Factored into these estimates, according to APHIS,
was the 20-day preharvest sampling and incubation of a small fraction
of fruit.
The very existence of the 20-day preharvest sampling and incubation
program ensures that the detection probability at this stage is
correlated with the incidence of citrus black spot or sweet orange
scab, since the detection probability is higher for higher incidences.
Thus, the structure of the risk assessment model is incorrect. It is
important also to note that the detection probability is correlated
with the actual incidence, not with the probability of citrus black
spot or sweet orange scab. The structure of the model has to be
adjusted to account for this. In a Monte Carlo analysis, for example,
the simplest way is to ensure that the detection probability at this
stage depends correctly on the incidence in the particular Monte Carlo
sample.
APHIS provides no documented evidence for the effectiveness of
packinghouse inspections in either the risk assessment or the
rulemaking record. The Argentines provided experimental data on the
effectiveness of ``post-harvest treatments'' or ``post-harvest assays''
that presumably assessed all events occurring at the packinghouse, but
again, because of the failure to provide protocols, experimental
details, scientific reports, and field notes in the risk assessment or
elsewhere, we cannot decipher what ``post-harvest treatments'' or
``post-harvest assays'' means. We believe that all the ``post-harvest
treatments'' or ``post-harvest assays,'' perhaps including any
inspections, have essentially no effect on the incidence of latent
infections of citrus black spot. Should it be necessary to evaluate the
effect of packinghouse inspection, as distinct from further
packinghouse treatment, the experimental procedure would be
straightforward, since all that is required is sampling of fruit prior
to and after such inspection (and preferably, also, sampling of
rejected fruit).
Response: The commenter's statement that ``The very existence of
the 20-day preharvest sampling and incubation program ensures that the
detection probability at this stage is correlated with the incidence of
citrus black spot or sweet orange scab, since the detection probability
is higher for higher incidences'' is incorrect. The packinghouse
inspection and our estimates regarding the likelihood of detecting
pests during this inspection are independent of both the 20-day
preharvest sampling protocol and the results of that sampling. If any
disease is detected as a result of the 20-day preharvest sampling, none
of the fruit from that grove can be shipped to the United States. The
only fruit that will be inspected and subsequently shipped to the
United States are fruit from groves where the 20-day preharvest
sampling resulted in a finding of no disease. The 20-day preharvest
sampling that would be conducted to detect the presence of citrus black
spot in the grove was accounted for in the risk model in P1, the
likelihood that harvested fruit is infected. This sample must be taken
from all groves that would ship fruit to the United States.
The commenter's statement that ``[i]t is important also to note
that the detection probability is correlated with the actual incidence,
not with the probability of citrus black spot or sweet orange scab'' is
likewise incorrect. The likelihood that diseased fruit will be detected
during packing is not related to disease incidence. Although the number
of times that diseased fruit are detected is related to disease
incidence (i.e., more disease, more detections), the likelihood that
diseased fruit will be detected is not correlated with disease
incidence.
In stating ``APHIS provides no documented evidence for the
effectiveness of packinghouse inspections in either the risk assessment
or the rulemaking record,'' the commenter is correct. These
packinghouse inspections have not yet been conducted. Our estimates are
based on examinations of citrus packinghouses in Argentina, experience
with inspections and culling in citrus packing operations, direct
knowledge of the etiology of these diseases, and familiarity with the
symptoms of these diseases.
Comment: APHIS estimates the effect of post-harvest treatments on
citrus black spot survival (on a per-box basis, which itself may not be
appropriate) as giving a mean survival of 0.64 in the baseline
situation, and a mean of 0.50 under the mitigation program. APHIS
appears to have ignored the results of experiments apparently designed
to test the effects of post-harvest treatments. Since APHIS does not
document how it arrived at its estimates, it is impossible to tell
whether it examined these data. There are no APHIS analyses of the data
in the risk assessment or the rulemaking record, but the assumptions in
the risk assessment for probability distributions appear to be
contradicted by these data.
Response: The ``results of experiments'' referred to by the
commenter are found in Argentine document Nota S.P. No. 338, which
contains a summary of experiments to test the efficacy of post-harvest
treatments on citrus black spot. Our analysis of that document
indicates that the treatment effects were variable; compared to
untreated controls, the proportion of treated fruit that developed
black spot disease ranged from 30 to 100 percent. The primary
difference between the treatments Argentina will use as part of its
regular program (what we refer to as the baseline risk) and the
treatments it will use as part of the program for exporting fruit to
the United States (the proposed treatment program) is the sodium
hypochlorite treatment. We did not ignore the results of the Argentine
experiments, as the commenter asserts; rather, we believed that it
would not be appropriate to assume that the difference in efficacy
shown in the experiments, which compared treated to untreated fruit,
would be the same as the difference in efficacy between the baseline
scenario and the mitigation scenario examined in the risk assessment.
This is because most of the treatments applied in the experiments cited
by the commenter were,
[[Page 37646]]
appropriately, considered in the risk assessment's examination of the
baseline risk, as those treatments are routinely applied by citrus
producers in Argentina as part of their regular program. Therefore, as
documented in the risk assessment (8.f P4), our estimates for the
mitigated scenario focused on the degree of additional risk reduction
offered by the sodium hypochlorite treatment, which we assumed would
have an additional deleterious effect on the survival of the citrus
black spot fungus. The increased level of efficacy of the mitigation
program is modest, a probability of 0.50 that the fungus will survive
treatment as opposed to a probability of 0.64 in the baseline scenario.
The primary purpose of these treatments is to reduce post-harvest
spoiling, not kill fungus diseases, and the main effect of the chlorine
dip is to kill spores on the surface of the fruit.
Comment: Since there is no information in the rulemaking record on
the protocols for the experiments on the effectiveness of post-harvest
treatments, nor any scientific documentation, we have to make some
plausible assumptions in order to perform the simplest analysis. Assume
that each experiment measures the disease rate in control and treated
fruit, with the disease rate possibly differing in all the replicates
of all the experiments. Assume that the post-harvest treatment alters
the disease rate in the corresponding control by a fixed factor Q (by
inspection, there is little difference within any set of replicate
experiments; while one could and should formally test for equality, our
simple analysis will forgo that testing for the sake of brevity).
Assume that the same factor Q applies to all the experiments on a given
fruit (again, this could and should be formally tested). Assume
binomial distributions for infection, as would occur if the fruit were
randomly chosen. Then the maximum likelihood estimates for Q are: 0.71
(grapefruit), 1.16 (orange), and 0.92 (lemon).
It should be noted that for this analysis, we have assumed that the
detailed tables included in the rulemaking record and largely
corresponding to the summaries provided by Argentina in Note S.P. 338,
Annex III, are correct, and we have treated discarded fruit as though
they were diseased. There are significant differences between those
tables and the summaries presented by Argentina in Annex III in the
descriptions of the number of fruit examined, and one table (Orange,
Third Replicate) has the control and T2 groups transposed for all
observations Rl, R2, R3, and R4. Once again, we are hindered by the
absence of protocols, scientific documentation, and field notes from
the rulemaking record. For example, whether discarded fruit should be
analyzed as though infected depends on experimental details that are
not presented within the rulemaking record, and even the summary tables
in the record are inconsistent in their treatment of such discards.
There are no comments by APHIS in either the risk assessment or the
rulemaking record on these significant discrepancies.
These experimental results indicate that the post-harvest
treatments have little, if any, effect on latent infections of citrus
black spot. It would be possible to find confidence limits and test for
equality of effect, but the effort would be wasted given the tiny
number of experimental conditions, and the likelihood for variation
(beyond the assumed binomial randomness) with field conditions, fruit,
and possibly experimental conditions. The results do, however, throw
considerable doubt on the values used for Q in the risk assessment for
citrus black spot (0.64, range 0.4 to 0.85).
Response: In this comment, the commenter states in several places
that there is no information in the rulemaking record on the protocols
for the experiments on the effectiveness of post-harvest treatments for
citrus black spot. In fact, the Argentine document to which the
commenter refers, Note S.P. 338, states that ``[t]he results that
appear in Annex III are the results of the assays that were carried out
applying the methodology informed [sic] to APHIS in the `Protocol of
Assays to Evaluate the Effectiveness of the Post-Harvest Treatments for
the Control of Guignardia citricarpa in Citrus Produced in the North-
West of Argentina (NOA)' * * *.'' That document, which is actually
titled ``Assays to Test Effectiveness of the Postharvest Treatment for
the Control of Guignardia citricarpa in Citrus Fresh Fruit Produced in
Argentine Northwest Region (NOA),'' was provided to the commenter
following the close of the comment period and is included in the
material provided in the addendum to the risk assessment that may be
obtained from the person listed under FOR FURTHER INFORMATION CONTACT.
In discussing discrepancies that he believes exist among varies
documents in the record, the commenter first states that the ``detailed
tables,'' which are not identified in the comment, ``largely''
correspond to the summaries in Annex III of Note S.P. 338, and then
states in the next sentence that there are ``significant differences''
between those tables and the summaries in Annex III. Without specific
information as to where the differences occur, we are unable to provide
the commenter with any clarification regarding possible discrepancies.
The commenter concludes, as a result of the simple analysis set
forth in his comment, ``that the post-harvest treatments have little,
if any, effect on latent infections of citrus black spot.'' We
acknowledged this in the risk assessment and recognized that the
primary purpose of these treatments is to reduce post-harvest spoiling,
not kill fungus diseases, and the main effect of the chlorine dip is to
kill spores on the surface of the fruit. The expert information used in
the risk assessment reflected the variability of the treatment data and
the experts' uncertainty around those data. While assuming that the
fungicidal and chlorine dips would have a deleterious effect on the
viability of Guignardia citricarpa propagules, the experts recognized
the latent nature of black spot infections. The germinating fungal
spore forms an appressorium from which an infection peg penetrates the
cuticle, and mycelium grows in between the cuticle and the epidermis
where it may remain quiescent (Whiteside, 1988) and effectively
protected from fungicidal treatments. However, the form in which the
fungus remains after treatment (i.e., mycelium) can hardly be
considered infective (McOnie, 1967). The experts predicted that between
10 and 90 percent of infected boxes would survive post-harvest
treatment with a most likely value of 50 percent.
In our response to the previous comment, we discussed the data
provided by Argentina on this subject and our analysis and
interpretation of those data. As we noted in that response, we assumed
that the addition of the sodium hypochlorite dip to the baseline post-
harvest treatments would have an additional deleterious effect on the
survival of the citrus black spot fungus, but that the increased level
of efficacy would be modest, reducing our estimate of the probability
that the fungus will survive treatment from 0.64 (baseline) to 0.50
(mitigated).
Comment: For sweet orange scab, APHIS admits to having no efficacy
data for the post-harvest treatments and provides no documentation of
its method of reaching the values used in the risk assessment.
Comparison with the citrus black spot case, where some data are
available, leaves considerable doubt as to the adequacy of APHIS's
methodology. In any case, it would be relatively straightforward to
perform
[[Page 37647]]
efficacy studies using methodology similar to that used on citrus black
spot, and there is no indication of why such studies have not been
performed for sweet orange scab.
Response: As noted by the commenter and in the risk assessment, no
specific sweet orange scab efficacy data were available for the
fungicidal activity of any of the individual post-harvest treatments
that might be employed in the proposed export program. The incidence of
sweet orange scab in a test sample of fruit subjected to the entire
preharvest, harvest, and post-harvest export program was described in
Argentine document 450/96 (September 30, 1996). In this survey, 300
boxes of fruit were randomly chosen from a larger lot that had been
subjected to the conditions of the export program. Ten fruit were
collected from each of the 300 boxes and visually inspected for
symptoms of sweet orange scab. None of the 3,000 total fruit examined
expressed disease symptoms. However, the survey did not include
controls and its design did not allow for the separation of the effects
of field treatments, inspections, or post-harvest treatments. The data
provided by this survey were nonetheless useful in illustrating the
effectiveness of the measures required by the export program and, when
combined with the considerations discussed in the next paragraph, led
us to conclude that additional studies such as those suggested by the
commenter would not be necessary for the purposes of our risk
assessment.
As we have noted elsewhere in this document and in the risk
assessment, the only additional post-harvest treatment specifically
required by the proposed export program (compared to the baseline) is
the sodium hypochlorite dip. We assumed that the sodium hypochlorite
dip--a treatment with widely recognized antifungal efficacy--would
further reduce the survival rate of the sweet orange scab pathogen. An
important consideration taken into account by our experts is the fact
that, unlike citrus black spot, sweet orange scab lesions are erumpent
and exposed on the surface of the rind. Thus, our experts believed that
the sodium hypochlorite dip, along with the fungicidal treatments found
in both the baseline program and the proposed export program, would be
effective in killing any viable conidia on the surface of a pustule or
contaminating the rind of fruit and may have some minor effect on sweet
orange scab stomatic tissue.
Comment: For citrus canker, APHIS cites literature efficacy studies
on the effect of chlorine dips. However, the method by which
probability distributions were assigned from this literature is
undocumented.
Response: The chlorine dip was only one factor considered when
estimating the appropriate value for model inputs for this node (P4).
The efficacy data on chlorine dips were considered along with other
data and information, as cited on p.39 of the risk assessment:
These treatments may include, but are not limited to, washing
fruit in a detergent bath, waxing and fungicide dips. The only post-
harvest treatment for pathogens that is specifically prescribed in
the proposed export program is a fruit dip in 200 ppm sodium
hypochlorite (bleach) for 2 minutes.
The probability distribution resulted from the expert judgment of a
group of three plant pathologists familiar with treatment of commercial
fruit for export, after consideration of all pertinent, available
information. References for that information were provided in the risk
assessment.
Comment: The proposed rule calls for testing 320 fruit/200 ha,
according to SENASA's randomized sampling protocol, a protocol that is
not described in the proposed rule or the risk assessment. We believe
that the presence of such a testing procedure alters the structure of
the model that must be used for the risk assessment. It also appears
that such a testing procedure is designed to fail--we believe that
fruit with a startlingly high infection rate could pass through such a
screen.
From the information provided in the rulemaking record, total
citrus production in northwestern Argentina appears to have been about
20 tons/ha in 1989, indicating yields similar to those in California
and Florida (20-40 tons/ha). The tree planting densities also appear
similar (200 to 250 trees/ha). Thus, for lemons, at 150 fruit per 18-kg
box (as assumed in the risk assessment), the lemon yield will be about
170,000 to 340,000 per ha, and the total area required to produce the
1,200,000 boxes examined in the risk assessment will be about 600 to
1,000 ha.
For the sake of argument, assume that Argentina sets up 20 groves
each of 100 ha as potential U.S. export groves, and follows all the
procedures of the proposed rule (and note that this is, at first sight,
about twice the required area). A 100 ha grove might have a buffer zone
of 69 ha, so that the total area of the grove plus buffer would be 169
ha, calling for a sample of 270 fruit per grove+buffer (assuming that
the buffer has to be sampled, but that is ambiguous in the proposed
rule).
Now suppose that all the fruit from all the proposed U.S. export
groves are infected at a rate of 1 in 400 fruit (0.25 percent), which
is fairly high, just 100 to 400 times lower than the unmitigated rate.
The probability for no infected fruit in a random sample of 270 fruit
is (1-0.0025)<SUP>270</SUP> = 0.5. Thus one could expect about 10 of
the 20 groves to pass this test, providing the necessary area of 1,000
ha, while the other 10 groves would be removed from the export program
for this season. The next season, the same thing might happen, but with
a different (random) set of 10 or so groves excluded, and 10 or so
included. Examination of this scenario and its extensions shows that
with suitable subdivision of the potential U.S. export acreage into
groves, and acceptance that some groves each year will be randomly
removed from the program, almost any infection rate in the fruit is
possible under the sampling scheme suggested. That is, the sampling
scheme is not effective at controlling the allowable infection rate.
There is no need to postulate a deliberate effort to outwit the
sampling scheme. It might prove economically advantageous for the
citrus-producing region of northwestern Argentina to adopt all the
procedures of the proposed rule for the entire citrus producing region,
since such procedures may produce superior yields for many markets, not
just the United States. Only a very small fraction of groves would have
to meet the testing requirements to generate the suggested export
volumes; and with the proposed sampling approach, these are likely to
occur randomly even if the infection rates are higher than the 1-in-400
fruit of the preceding example. It would be straightforward to design
statistically adequate sampling and testing regimes to ensure that the
overall infection rate of fruit from any grove is below any required
value, and such schemes can be extended to account for nonuniform
infection rates between groves, and even infection rates that vary
within each grove, but there is no evidence in the record of any such
attempt.
Response: We disagree with the commenter's statement that a testing
procedure that calls for a certain number of fruit to be collected from
a defined area ``alters the structure of the model that must be used
for the risk assessment.'' If the model we used in the risk assessment
was a scenario tree model with branches that were based in some way on
the outcome of the sampling, then the sampling protocol might have an
impact on the structure of that model. In simple terms, the outcome of
the sampling determines whether the fruit produced in an export grove
will be considered in the export program, since the detection of
disease
robop...@us.govnews.org
Posting-number: Volume 65, Issue 116, Page 37607, Part 1
[[Page 37632]]
Response: The objective criteria we use to rate the five risk
elements are stated on pages 22 through 25 of the risk assessment, and
our findings regarding the five risk elements are provided on page 26.
Our findings are not based on ``broad uncharacterized assumptions,''
but on specific information available in the scientific literature. The
information used in rating each pest is provided in the pest data
sheets provided for each of the rated pests (Appendix I-IV for four
species of fruit flies and Appendix V-VII for the three citrus
diseases), which are supported by the scientific literature cited and
listed in each pest data sheet.
We did not discuss the role of uncertainty in the assignment of
ratings for the five risk elements because uncertainty played an
insignificant, if any, role in the assignment of those ratings. For
each risk element, each pest received a qualitative ranking of high,
medium, or low; the assignment of each ranking for each pest was
dictated by the responses to specific and objective criteria. For
example, the rankings assigned for Risk Element #2 (host range) were
assigned as follows:
<bullet> High--Pest attacks multiple species within multiple plant
families.
<bullet> Medium--Pest attacks multiple species within a single
plant family.
<bullet> Low--Pest attacks a single species or multiple species
within a single genus.
As can be seen in the pest data sheet included in the risk
assessment for each of the pests examined, the host range of each pest
has been established and documented, so there was no uncertainty
involved in the assignment of a qualitative risk rating for each pest
under this risk element. The same may be said for the other four risk
elements as well, with the possible exception of Risk Element #5
(environmental impact), in which three of the five factors considered
involve expected impacts on the environment or on threatened/endangered
species. Because those factors involve likely future impacts as opposed
to documented past impacts, some degree of uncertainty is inevitable;
however, we do not believe that the level of uncertainty is sufficient
to have had any substantive impact on the assigned risk ratings.
Comment: Climate-host interaction is estimated solely on the USDA s
Plant Hardiness Zone Map. This map provides temperature zones for
specified regions, and risk is calculated based on a pest's ability to
exist in one to several temperature zones. Yet, rainfall and relative
humidity play an equally critical role in the ability of a disease
pathogen to survive and thrive in a new area. (For example, there is
the added moisture that results from irrigation and fog, as in the
coastal California growing areas, and the summer monsoon season that
occurs in both Arizona and southern California.) The omission is never
mentioned, so neither is the uncertainty this omission represents.
Response: The plant hardiness zone map is used in the discussion of
Risk Element #1, ``Climate-Host Interaction,'' as an objective means of
specifying the extent of the potential range of the pest. We agree that
it may be appropriate, as suggested by the commenter, to introduce
relative humidity and rainfall as factors for consideration at this
stage. However, the addition of those factors at this stage would have
the effect of further limiting the potential range of the pest under
consideration to areas even smaller than temperature zones, as the pest
would be restricted to areas with appropriate ranges of multiple
factors (temperature, rainfall, and relative humidity), rather than
just one factor (temperature). That being said, the role of moisture is
in fact considered in the risk assessment, contrary to the commenter's
assertion that it was not. Specifically, Risk Element #3, ``Dispersal
Potential,'' considers ``whether natural factors (e.g., wind, water,
presence of vectors) facilitate dispersal'' as one of the three items
examined when evaluating whether a pest has the potential to disperse
(or, to use the commenter's terminology, ``survive and thrive'') after
introduction into a new area.
Comment: Sweet orange scab is rated medium for its host range
potential yet it is not known to infect genera of Rutaceae other than
Citrus species. Citrus black spot is rated high for its dispersal
potential (capable of movement over 10 km per year), yet the scientific
data, and the data sheet provided, indicate that this fungus only
spreads short distances under natural conditions. Long-distance
dispersal is attributed to the artificial movement of citrus leaves and
nursery stock, both of which are beyond the scope of the risk
assessment. If this assessment is correct, the 150-meter buffer
provision in the proposed program should be reexamined.
Response: Our understanding of this comment is that the commenter
is pointing out that: (1) The rating we assigned for the host range
potential of sweet orange scab was too high and (2) the rating we
assigned for the dispersal potential of citrus black spot may have been
too high, and if that is the case, the 150-meter buffer zone may be too
large. We agree that Elsinoe australis (sweet orange scab) could have
received a rating of ``low'' for host range potential and, as a result,
sweet orange scab could have only been rated as ``medium''--not
``high''--for its consequences of introduction. Similarly, Guignardia
citricarpa (citrus black spot) could have been rated as ``medium'' for
dispersal potential, and as a result, citrus black spot could have been
rated as ``medium''--not ``high''--for its consequences of
introduction. Although our original rating of ``high'' for the
dispersal potential of citrus black spot may have been somewhat
conservative, we believe that the 150-meter buffer zone provision is
still an appropriate measure to protect production groves from
neighboring properties that are not participating in the export
program.
Comment: Black spot is apparently on a wide range of other host
plants. The risk of movement of Guignardia citricarpa on latently
infected fruit and its ability to establish in a new area on various
other hosts (i.e., not citrus) is underrated.
Response: Guignardia citricarpa is morphologically identical to
another Guignardia sp. that is latent in citrus and many other hosts.
However, the identified host range of Guignardia citricarpa is limited
to commercially grown Citrus spp. except for sour orange (C. aurantium)
and its hybrids. Given the identified host range of Guignardia
citricarpa, we believe that the risks presented by Guignardia
citricarpa were appropriately rated in the risk assessment.
Comment: The likelihood of introduction is estimated using
probabilistic scenario analysis. Here, uncertainty is addressed in the
probability distributions, but these distributions were in turn based
upon a number of assumptions that are not explained. Among other
criteria, pest risk assessments must contain sufficient detail and
identify all sources of uncertainty in data extrapolation in order to
be open to evaluation and review. It is for this reason that the FAO
Guidelines for Pest Risk Analysis require that the analysis or
assessment clearly state the sources of information and the rationales
used in reaching decisions regarding the phytosanitary measures
proposed.
Response: Our risk assessment was conducted with strict adherence
to the FAO guidelines. As explained in the risk assessment on p. 28, we
estimated model inputs ``using the best available data and expert
judgment as our basis.'' In those cases where data were available, we
identified those data and the role they played in the development of
our distributions. When data were not available, we used additional
[[Page 37633]]
information provided by our experts to arrive at estimates that
reflected what we considered to be appropriate levels of uncertainty,
and the distributions were derived to reflect those estimates; in those
cases, the role of expert judgment or expert information in arriving at
the estimates was acknowledged. We believe, therefore, that our risk
assessment clearly states the sources of information and the rationales
used in reaching decisions regarding the phytosanitary measures
proposed as required by FAO.
Comment: Although some background information was provided, it
would have been extremely helpful to include some additional
information within or accompanying the pest risk assessment. This would
include a complete review of current pest status of citrus black spot
and sweet orange scab in Argentina and in the four States; the trip
reports for any and all site visits; all survey methods and results;
and a complete discussion of Argentina s current and proposed control,
harvesting, and packing procedures.
Response: All of the information cited by the commenter is either
in the public domain or is part of the rulemaking record, which was
made available to the commenter. We do not believe that it would be
feasible or even necessary to reproduce the entire public record in the
risk assessment.
Comment: APHIS has not adequately considered the risk of
infestation and infection originating in residential areas.
Response: The risk of infestation/infection in residential areas
was considered in the risk assessment as part of input probabilities P6
(fruit transported to suitable habitat), P7 (pest finds/pathogen
reaches suitable host), and P8 (pest/pathogen able to complete life
cycle). Those input probabilities considered both commercial production
areas as well as residential areas.
Comment: The mitigation scenarios for the fruit flies and citrus
canker are estimated against the systems approach proposed for citrus
black spot and sweet orange scab; there is no analysis provided for the
efficacy of the direct mitigation measures proposed for these pests.
For the fruit flies, it would be more relevant to provide the
supporting data evidencing the effectiveness of the post-harvest cold
treatment. For citrus canker, it would be more appropriate to show how
this program meets the requirements for designation of a pest free
area.
Response: It is not the case that ``the mitigation scenarios for
the fruit flies and citrus canker are estimated against the systems
approach proposed for citrus black spot and sweet orange scab.'' The
risk presented by each pest was analyzed individually with respect to
pertinent mitigation measures. In fact, we state on page 32 of the risk
assessment that the baseline treatments of washing, waxing, and dipping
the fruit (for diseases) ``are expected to have only a minor effect on
fruit flies.'' Our estimates do not include any reduced fruit fly risk
from these treatments. As shown in Table 7 on p. 35 of the risk
assessment, there are only two differences between the risk model
inputs for the baseline (no specific mitigations) and the proposed risk
mitigation program. That is, two of the nodes were affected by the
proposed program. The first affected node is P5 (pest survives post-
harvest treatment). As described on p. 32, all of the reduced
likelihood of fruit fly survival with the proposed program comes
directly from the cold treatment for fruit flies:
USDA has an approved cold treatment schedule for both Ceratitis
capitata, Treatment T107(a), and Anastrepha fruit flies other than
A. ludens, Treatment T107(c) (PPQ, 1992). The treatment schedule
allows different temperature/time combinations to be used. For
example, T107(a) allows 32 deg. F (or below) for 10 days as well as
36 deg. F (or below) for 16 days. Treatment schedules were based on
demonstrated efficacy of probit 9 (99.9968 percent) mortality. This
corresponds to a survival rate of 0.00003 (0.003 percent). We
represented survival as a lognormal distribution with a mean of
0.0001 and a standard deviation (sd) of 0.00011. A sd of 0.00011 was
chosen because the resulting distribution has a mode (peak of the
distribution) at 0.00003.
The other node that is different is P8 (pest able to complete life
cycle). As explained on p. 33 of the risk assessment, we estimated that
this value would be slightly lower as a result of the cold treatment
for fruit flies. The reduced risk from fruit flies under the proposed
program results from the cold treatment for fruit flies, and not from
the treatments applied for the diseases of concern.
Regarding citrus canker, three main components are considered in
the establishment and subsequent maintenance of a pest free area:
Systems to establish freedom, phytosanitary measures to maintain
freedom, and checks to verify freedom has been maintained. Argentina
established its freedom from citrus canker, as stated on page 36 of the
pest risk assessment, through 4 years of comprehensive specific surveys
with negative results as well as general surveillance for canker in the
field and in published literature. Argentina continues to maintain area
freedom through phytosanitary measures outlined on pages 27 and 36 of
the pest risk assessment document. These phytosanitary measures include
restrictions on the movement and planting of citrus nursery stock in
the free area and domestic quarantine controls at airports and roads
servicing the area. Continuing canker surveys, field and packinghouse
inspections, and the requirement for a phytosanitary certificate help
verify that area freedom is maintained.
Comment: The probability estimate for ``harvested fruit is infected
with citrus black spot and sweet orange scab'' is based on limited
field survey data provided by Argentina. For example, treatment tests
for grapefruit were performed on young trees in 1994 only, i.e., trees
known not to show symptoms with or without fungicidal treatment. The
1994-95 treatment data provided are for oranges only, and the age of
the orchard trees is not provided. There were no data provided for
lemons, the most susceptible citrus for citrus black spot infection. No
treatment data were provided for sweet orange scab.
Response: We acknowledged in the risk assessment that the survey
data provided by Argentina was limited. In the discussion of node P1,
``Harvested fruit is infected,'' we stated that ``our estimates * * *
were based on limited field survey data provided by Argentina and
expert information provided by scientists familiar with citrus
production in Argentina and/or the pathogen.'' Because the field survey
data were limited, we used additional information provided by our
experts to arrive at estimates of these probabilities that reflected
what we considered to be appropriate levels of uncertainty, and the
distributions were derived to reflect those estimates.
Comment: The probability estimate for ``pathogen not detected at
harvest'' is based solely on expert information that the fruit pickers
would be able to find and cull diseased fruit. It does not provide any
discussion regarding the latency period of citrus black spot symptom
expression, nor that symptom expression does not occur at all in fruit
from trees younger than 12 years. Yet, it does ironically assume in the
mitigation scenario, based on a program that suppresses symptom
expression, that this activity would result in fewer citrus black spot
infected fruit escaping detection.
Response: In that latent infections would not be visible to pickers
during harvest, we do not believe that it is necessary for the
probability estimate for P2 (pathogen not detected at harvest) to
provide a discussion regarding the latency period of citrus black spot
symptom expression or the lack of symptom expression in all fruit from
[[Page 37634]]
trees less than 12 years old. Rather, the issues of latency and lack of
symptom expression are considered in, and factored into, the
probability estimates provided in P3 (pathogen not detected at packing
house inspection) and P4 (pathogens survive post-harvest treatment).
With regard to the last sentence of the comment, the systems approach
is not, as the commenter states, a ``program that suppresses symptom
expression.'' Rather, as we have stated elsewhere in this document, the
treatments and cultural practices required by this rule are designed to
prevent fruit from becoming infected in the first place. Those
requirements are the basis for the risk assessment's expectation that
``more rigorous export standards and reduced frequency of latent
infection would result in fewer [citrus black spot] diseased fruit
escaping detection.''
Comment: The probabilistic estimate for ``pathogens survive post-
harvest treatment'' predicts that these minimal treatments would have a
deleterious effect on the survival of both sweet orange scab and citrus
black spot causal pathogens. What this estimate does not state is that
this node only applies to pathogen spores that may be found
contaminating the surface of the fruit and that the fruit at that point
is resistant to infection.
Response: It is correct that mature fruit is not susceptible to new
infection and that the post-harvest treatment is intended to render
nonviable any spores contaminating the surface of the fruit. This is
reflected in the risk assessment's discussion of node P4, ``Pathogen
survives post-harvest treatment,'' where we stated that ``[w]e assumed
that the additional treatments [i.e., the chlorine dip] included in the
proposed export program would further reduce the survival rate of the
[sweet orange scab] pathogen'' and that ``[f]or our mitigated scenario
we assumed that the chlorine dip would have an additional deleterious
effect on the survival of the [citrus black spot] fungus.'' As noted
elsewhere in this document, these post-harvest treatments are mainly to
prevent post-harvest decay.
Comment: In section 8.f, ``Inputs, Sweet orange scab, citrus black
spot and citrus canker,'' the probabilistic estimate for ``fruit
shipped to a suitable habitat'' is based solely on the percentage of
geographical area that supports cultivation of citrus. Yet, in fact,
this node would be more accurate if estimates were based on population
densities, as fruit is going to be shipped based upon a target market,
not geography. Then, a comparison should be made relative to the
population percentage found within the citrus growing areas. As it is
estimated now, this node is particularly likely to be grossly
underestimated. The probabilistic estimate for ``pathogen reach
suitable host'' is based on an assumption that the initial inoculum
source was introduced into an orchard setting. In fact, it is much more
likely that the inoculum will initially be introduced into an urban
setting. As a result, this node is another one that is particularly
likely to be grossly underestimated. This probability node, along with
the one above, should be recalculated more appropriately.
Response: We disagree with the commenter's statement that the
probabilistic estimate for ``fruit shipped to a suitable habitat'' is
likely to be grossly underestimated. With the large citrus markets
throughout the United States, we have no reason to believe that our
estimate of 5 percent (percentage of imported fruit that will be
shipped to areas where citrus can survive) is too low or too high, nor
have we received any specific information from any commenter that would
allow us to change our estimate. (Note: Tables 8-10 on pp. 44-46 of the
risk assessment correctly list our estimate as 5 percent, and this is
the value used for the calculations. The text on p. 41 incorrectly
states this value as 9 percent). While it is accurate to state that
fruit will be shipped based on markets rather than geography, one
cannot dispute the link between geography and suitable habitat. The
ability of an area to support a pest population is a function of
climate and the availability of host material, and not population
density.
Similarly, the commenter's statement that ``the probabilistic
estimate for `pathogen reach suitable host' is based on an assumption
that the initial inoculum source was introduced into an orchard
setting'' is inaccurate. We can find no statement in the risk
assessment that could lead the commenter to this conclusion. We stated
in the risk assessment:
All three pathogens analyzed are essentially restricted to
citrus hosts (or closely related species). Suitable habitat for
these organisms necessarily corresponds to the range of their citrus
hosts. Consequently, we considered the citrus growing regions of the
continental United States to be ``suitable habitat.'' We estimated
the percentage of the area of the contiguous 48 States that supports
the growth of citrus species.
This percentage of the area of the contiguous 48 States that
supports the growth of citrus species includes all areas where citrus
fruit can be produced, including ``backyard trees'' in urban, suburban,
or rural settings, or any other areas where citrus plants can survive
and produce fruit, as well as commercial citrus-production areas.
However, citrus is a subtropical plant and can only survive and produce
fruit in a small portion of the continental United States. Accordingly,
we do not agree with the commenter's statement that both nodes are
grossly underestimated and need to be recalculated.
Comment: The probabilistic estimate for ``pathogen able to complete
disease cycle'' in particular should evaluate the effect of the systems
approach, i.e., it should provide a measurement of the level of
infection and an estimation as to risk from latent or suppressed
symptom expression. It should also include a discussion of the role of
pycnidiospores in disease establishment and episode development.
Although citrus black spot epidemics tend to be caused by the
ascospores produced on dead leaves, the pycnidiospores from fruit are
quite capable of being the source of introduction of the disease. The
risk assessment should give more careful consideration to the
pathogenicity of the pycnidiospores and should consider the possibility
that citrus black spot could become established in the United States
through pycnidiospores infecting residential citrus.
Response: Our understanding of the commenter's suggestion that
``[t]he probabilistic estimate for `pathogen able to complete disease
cycle' * * * should evaluate the effect of the systems approach, i.e.,
it should provide a measurement of the level of infection and an
estimation as to risk from latent or suppressed symptom expression'' is
that the commenter believes that the intended effect of the systems
approach is to suppress the symptoms of citrus black spot and, on the
basis of that belief, that we should estimate the percentage of fruit
that will be latently infected and provide an estimate of the risk
presented by that latently infected fruit. As we have stated elsewhere
in this document, we disagree with the commenter's assertion that the
goal of the systems approach is simply to suppress symptoms; rather,
the systems approach is intended to prevent infection in the first
place, provide for the detection of infection if it should occur, and
prevent the entry of infected fruit into the United States. That being
said, this node of the risk assessment (P8: Pathogen able to complete
disease cycle) is assumed to be an independent event and, as such,
begins with the assumption that the pest, in some form, has reached a
suitable habitat and a
[[Page 37635]]
suitable host, including residential citrus. The node then describes
``our estimate of the likelihood that these pathogens would, having
reached a host plant, be able to infect that plant and complete the
disease cycle.'' Thus, we believe that the risk assessment does in fact
provide the estimation of risk sought by the commenter in the first
part of her comment.
In the second part of her comment, the commenter suggests that this
node of the risk assessment ``should also include a discussion of the
role of pycnidiospores in disease establishment and episode
development.'' In our discussion of this node in the risk assessment,
we stated that we ``took into account the type of infectious propagule
produced by each of the three pathogens and the environmental and
physiological requirements for host plant susceptibility and successful
disease progression'' and later, specifically with regard to citrus
black spot, that:
The epidemiology of [citrus black spot] is influenced by the
availability of inoculum, the environmental requirements for
infection, the growth cycle of the host and the age of the fruit in
relation to its susceptibility. Ascospores formed on dead leaves on
the orchard floor form the main source of inoculum, however pycnidia
on out of season or late hanging fruit can also serve as sources of
rain splashed inoculum. Spores are released during rainfall and
during irrigation. Except for lemons, leaf infections seldom occur.
The critical period for infection starts at fruit set and lasts for
4 to 5 months. Symptom development is hastened by rising
temperatures, high light intensity, drought and poor vigor.
Given the above discussion, we believe that we did give due
consideration in the risk assessment to the pathogenicity of the
pycnidiospores and the possibility that citrus black spot could become
established in the United States through pycnidiospores infecting
residential citrus. Our estimates of the risk presented by
pycnidiospores are supported by the American Phytopathological
Society's (APS) Compendium of Citrus Diseases (Whiteside, J.O.,
Garnsey, S.M. and Timmer, L.W., 1988, APS Press, American
Phytopathological Society, St. Paul, MN. 80 pp.), which is cited
repeatedly in the risk assessment. That publication states:
``Pycnidiospores formed on dead leaves on the ground can reach the
susceptible fruit only by the splashing of raindrops, and they are not
considered an important source of inoculum.'' The pycnidiospores play a
role in short distance water-dispersal of this disease. They may be
produced on symptomatic, late-hanging fruit or on dead, decaying leaves
on the orchard floor. Pycnidiospores from fallen leaves are very
unlikely to reach fruit because they are solely waterborne.
Pycnidiospores from late-hanging, symptomatic fruit can infect fruit
that is in physical contact with the infected fruit or that is hanging
below the symptomatic fruit, if the fruit are susceptible and
environmental conditions appropriate. This agrees with the findings of
McOnie (McOnie, K.C., 1964, ``Speckled blotch of citrus induced by the
citrus black spot pathogen Guignardia citricarpa,'' Phytopathology 54:
1488-1489), who concluded that ascospores are the major infective
bodies and that spores of the asexual stage (i.e., pycnidiospores) are
unimportant in producing fruit infections.
Comment: The pest risk assessment concluded that the pest risk
potential, minus the mitigation measures, is high for the fruit flies
and sweet orange scab and medium for citrus black spot; citrus canker
is not mentioned. No conclusions are expressed for the pest risk
potential as mitigated by the proposed program. In any case, sufficient
information necessary to assess the efficacy of the proposed systems
approach for sweet orange scab and citrus black spot is not available
within the proposed rule, the supporting pest risk assessment, or other
documentation provided.
Response: The pest risk potential of an organism, which can be
viewed as a constant, is not affected by mitigating measures, which is
why the risk assessment expressed no conclusions for the pest risk
potential as mitigated by the proposed program. Rather, it is the
likelihood of introduction that will be affected by the mitigating
measures, and we did provide our conclusions for the likelihood of
introduction as mitigated by the proposed program. Citrus canker is not
mentioned because fruit will be imported only from the citrus-canker-
free area of Argentina. With regard to the efficacy of those mitigating
measures, we believe that the data supplied by Argentina and the
reports of APHIS personnel who conducted the site visits in Argentina,
which are all part of the rulemaking record and were made available to
the commenter, as well as the information contained in the scientific
literature cited in the risk assessment, provided sufficient
information to support the risk assessment and its conclusions relating
to the risk reductions afforded by the mitigating measures required by
this rule.
Comment: In the risk assessment, APHIS states that it evaluated
only pests that can ``reasonably be expected to follow the pathway,
i.e., be included in commercial shipments of citrus.'' But the pathway
contains more than just commercial shipment, and much of the protection
estimated in the risk assessment for the diseases and pests evaluated
comes from other components of the pathway. What should matter is not
the probability of traversing the pathway as far as commercial
shipment, but the probability of completing the whole pathway. The
probability required for ``reasonably be expected'' appears to be
extremely high compared with the required levels of protection. It is
plausible that for other pests or diseases, other parts of the pathway
are not of low probability. In that case, the risk assessment has not
included sufficient pests.
Response: In stating that the pathway consists of ``more than just
commercial shipment'' and that protection may be afforded by ``other
components of the pathway,'' it appears that the commenter is confusing
the pathway itself with the mitigation measures applied to fruit in the
pathway. The only pathway ``opened'' by this rule, and thus the only
pathway appropriately considered in a risk assessment supporting this
rule, is the commercial shipment of citrus fruit from Argentina to the
continental United States. Other pathways (e.g., backyard fruit
smuggled by airline passengers or placed in the mail) would exist with
or without this rule, and thus did not fall within the scope of the
risk assessment prepared for this rule. Commercial shipment is the
whole pathway, and not merely a distinct stop along the pathway as the
commenter suggests when he speaks of ``traversing the pathway as far as
commercial shipment.'' In our risk assessment, the commercial shipment
pathway for citrus fruit begins in the Argentine production area and
ends in the continental United States in the ultimate consumer's trash
can or compost pile, and this entire pathway was considered when
assessing pest risk. The risk assessment lists all pests of citrus in
Argentina, and all pests that can reasonably be associated with this
pathway were analyzed in detail.
Comment: The desired result of a Monte Carlo analysis should be
carefully defined, whereas the risk assessment has no stated, well-
defined, goal. In our opinion, the goal that would provide the most
useful information would be an estimate (and its uncertainty) of the
average annual likelihood that the importation of Argentine citrus
fruit will result in a pest outbreak in the United States. If this is
the intended goal of the analysis,
[[Page 37636]]
APHIS must reconsider its use of any distributions that reflect year-
to-year variability. The distribution for the number of shipments of
fruit that will be shipped to the United States was constructed ``to
allow for variation in the frequency of shipments that might result
from variation in production, frequency of shipments that are cleared
for shipment, and variation in market demands in the United States.''
If the intended goal is to estimate an average likelihood of a pest
outbreak, APHIS should ignore year-to-year variability in this value
and instead construct a distribution that accounts only for uncertainty
in the value for the average number of shipments that will be shipped
to the United States. The same would apply for any other year-to-year
variabilities included in the probability estimates, unless they were
correlated. No explicit mention is made of such variabilities in the
discussions of the other probability estimates, but the discussion of
these estimates is inadequate. If there are correlations, such as that
explicitly discussed in section 8.e P8 of the risk assessment, then
such correlations have to be taken into account. One way to do so would
be to incorporate the year-to-year variability together with the
correlations in the modeling. Each iteration of the Monte Carlo
assessment would then require a nested loop that averaged over multiple
years in order to obtain the long-term average.
Response: We disagree with the commenter's statement that the risk
assessment has no stated, well-defined goal. The overall purpose of our
risk assessment is stated in the first sentence of that document, i.e.
``* * * to examine plant pest risks associated with the importation
into the United States of fresh citrus fruit grown in certain areas of
Argentina.'' Similarly, with regard to our use of Monte Carlo
simulation methods to account for uncertainty in estimating
probabilities, we stated the following in the first paragraph of
section 8, Likelihood of Introduction (the only section of the risk
assessment in which Monte Carlo simulation methods were used): ``For
the pests listed in Table 6, we estimate the likelihood of introduction
using a quantitative method referred to as `probabilistic risk
assessment' or `probabilistic scenario analysis.' The purpose of a
probabilistic risk assessment is to estimate the likelihood of an
undesirable outcome (bad event). The bad event is represented by the
endpoint of the risk model, i.e., introduction of a quarantine pest.
Our method has four basic components: Scenario analysis, development of
a mathematical model, estimation of input values for the likelihood
model, and Monte Carlo simulation * * *.'' Thus, the purpose of the
Monte Carlo portion of the risk assessment is also stated clearly,
i.e., to estimate the likelihood that quarantine pests will be
introduced.
The goal suggested by the commenter--to provide ``an estimate (and
its uncertainty) of the average annual likelihood that the importation
of Argentine citrus fruit will result in a pest outbreak in the United
States''--is a reasonable approximation of our stated goal with a
slightly different endpoint. As explained in the risk assessment,
``introduction'' of a pest means entry and establishment (i.e.,
reproducing, self-sustaining population of the pest). Pest outbreak is
one possibility for the next step if we were to continue our scenario.
We have used pest outbreak as our endpoint in previous risk
assessments. However, in this risk assessment, we chose pest
introduction as our endpoint. Use of pest introduction as the endpoint
is more conservative (more pest exclusionary) than using pest outbreak.
Estimates of the likelihood of outbreak would be lower than estimates
of introduction because additional events would have to occur before
the introduction would lead to an outbreak.
The commenter also states that ``APHIS should ignore year-to-year
variability in this value and instead construct a distribution that
accounts only for uncertainty in the value for the average number of
shipments that will be shipped to the United States.'' These remarks
are premised on the belief held by some risk assessors that variability
must be dealt with separately from uncertainty in all cases; however,
the utility of this approach in all cases has not been demonstrated. In
the case of our risk assessment, we believe that separating other forms
of uncertainty from variability (i.e., year-to-year) would obscure,
rather than illuminate, the issue. Commercial shipments of citrus from
Argentina have never entered the United States; there are no data that
would allow us to characterize the expected year-to-year variability in
quantity imported. Although the actual number of shipments would vary
on a year-to-year basis, the data do not exist to characterize that
variability. There is considerable uncertainty regarding the quantity
of shipments. That is why we used a normal distribution that is not
bounded above or below the mean.
Finally, with regard to the commenter's suggestion that we
incorporate year-to-year variability together with correlations in the
modeling, we did consider the implications of possible correlations
among the nodes, but we determined that there were not any correlations
that would affect the calculations in the Monte Carlo simulation.
Comment: APHIS uses a simple multiplicative mathematical model to
estimate the frequency of pest outbreaks in the United States. The
estimated number of shipments of citrus fruit is multiplied by eight
probability distributions to arrive at the final distribution for the
likelihood of a pest establishing itself in the United States. If each
stage of the process were truly independent of all preceding stages,
and if it were certain that all fruit would pass through each stage of
the process, then this would be a simple, accurate model to describe
the likelihood of an exotic pest establishing itself in the United
States. However, we do not believe that each stage is independent of
the all preceding stages, nor do we believe that it is certain that all
fruit will pass through each stage of the process. The risk
assessment's mathematical model should take into account the
correlation of the stages and potential for the failure of fruit to
pass through all those stages.
Response: We believe that the commenter has misinterpreted the risk
model as a graphical representation of the risk mitigation process,
which it is not. The steps in our model are consecutive--for example,
fruit must be harvested before it can be taken to the packinghouse--
which could give the impression of dependence, but the risks examined
at each step are independent; the risks examined in one node do not
have a direct impact on the risks examined in the next. Although
certain of the risk mitigation steps are represented in the risk model,
the model accounts for other steps (e.g., biological) that are
independent of human activities. For example, node P7 (figure 2 on page
30) is stated as ``pest locates suitable host.'' Clearly, this is not a
risk mitigation step that can be skipped, it is a representation of the
probability that a pest will find host material should it enter the
United States. This probability is not correlated with the other nodes.
The scenario should be viewed according to the description in the risk
assessment:
First, we use the method of scenario analysis to conceptualize
the events (referred to as nodes) that must occur before the
endpoint or ``bad event'' (e.g., introduction of Anastrepha
fraterculus or Elsinoe australis) can occur. Scenario analysis
provides a conceptual framework for assessing and managing risk.
Before the quarantine pest can
[[Page 37637]]
be introduced, all of the events shown in the model must occur.
Regarding the commenter's statement ``however, we do not believe
that each stage is independent of the all preceding stages,'' we
disagree and believe the nodes are independent; it is not possible to
address this comment more specifically without further information from
the commenter about which nodes he believes are correlated with others.
We have discussed the basis for our belief in the independence of the
nodes elsewhere in this document and address the issue in the addendum
that is available from the person listed under FOR FURTHER INFORMATION
CONTACT.
Regarding the commenter's statement ``nor do we believe that it is
certain that all fruit will pass through each stage of the process,''
we would point out that the probabilities assigned to each node that
represents a risk mitigation step relate directly to a ``failure'' of
that particular step (e.g., pest not detected, pest survives
treatment), thus the possibility of failure in each of the stages was
considered in the risk assessment. Further, this rule requires that
only fruit that passes through each stage of the process may be
approved for entry into the United States. SENASA inspectors will be
present at each stage to supervise, confirm, and document the
successful application of each of the required mitigations, and a
phytosanitary certificate issued by SENASA confirming that the fruit
has been produced in accordance with the requirements of this rule must
accompany each shipment of fruit exported to the United States.
Finally, the commenter states that we used our model to estimate
the frequency of pest outbreaks, but, as noted in our response to the
previous comment, that is not the case. As shown in Figure 2 on page 30
of the risk assessment, the endpoint of our risk model for the
likelihood of introduction was ``pest establishes.'' International
guidelines for pest risk analysis (FAO 1996, as referenced in the risk
assessment) define introduction as pest entry plus establishment.
Comment: APHIS selected an 18-kg box of fruit as the ``risk unit''
for the risk assessment and bases all estimates of probability on this
unit. This is not appropriate for all steps, perhaps any step, in the
analysis. For the first four stages of the pathway defined by the risk
assessment (i.e., until the fruit is boxed at the packinghouse), the
fruit are acted on independently of the boxes in which they will be
placed. Moreover, the processes of storage, sorting, and packing occur
in such a way that the fruit become fairly well randomized. Thus if
p<INF>1</INF>p<INF>2</INF>p<INF>3</INF>p<INF>4</INF> are the ``per
fruit'' probabilities designated as P1, P2, P3, and P4 on a ``per box''
basis in the risk assessment, then if
p<INF>1</INF>p<INF>2</INF>p<INF>3</INF>p<INF>4</INF> are independent
(but see below), the probability for a box containing n fruit to be
infection-free after the fourth stage is 1-(1-
p<INF>1</INF>p<INF>2</INF>p<INF>3</INF>p<INF>4</INF>) \n\. But this
cannot in general be written as the product P1P2P3P4 (as is done in the
risk assessment) where P1 through P4 are independent, and it cannot
even be so approximated if the product
p<INF>1</INF>p<INF>2</INF>p<INF>3</INF>p<INF>4</INF> is reasonably
large, as certainly occurs in the unmitigated situation. The natural,
indeed the only, unit for consideration is the individual fruit. Using
individual fruit will also allow straightforward analysis of the
experiments that have been or can be performed to test efficacy of
various treatments or actions.
Response: As noted elsewhere in this document, we believe that a
box of fruit is the most appropriate risk unit. No one unit is perfect
for each node; prior to packing there is mixing of the fruit from an
orchard. Once the fruit are packed, they are no longer independent of
each other, and it is boxes, and not individual fruit, that will be
shipped to--and, in all likelihood, remain in--specific destinations in
the United States. Even though no one unit is perfect for each node, we
decided that it would be most transparent, defensible, and correct to
use a consistent risk unit throughout the model. The primary problem
perceived with using individual fruit as the risk unit was the
different size of the various fruit being considered (i.e., lemons,
oranges, and grapefruit). Separate modeling for each type of fruit
would have complicated the assessment significantly and needlessly; the
expert group did not believe that separate modeling would improve the
accuracy of the risk estimates, especially given the inherent
uncertainties in the input parameters.
As explained in the risk assessment (section 8.e.F1, p. 29), in
each step of the scenario, the probabilities were estimated for one box
of fruit. The commenter asserts:
Thus if p<INF>1</INF>p<INF>2</INF>p<INF>3</INF>p<INF>4</INF> are
the ``per fruit'' probabilities designated as P1, P2, P3 and P4 on a
``per box'' basis in the risk assessment, then if
p<INF>1</INF>p<INF>2</INF>p<INF>3</INF>p<INF>4</INF> are independent
(but see below) the probability for a box containing n fruit to be
infection-free after the fourth stage is 1-(1-
p<INF>1</INF>p<INF>2</INF>p<INF>3</INF>p<INF>4</INF>) \n\. But this
cannot in general be written as the product P1P2P3P4 (as is done in
the risk assessment) where P1 through P4 are independent, and it
cannot even be so approximated if the product
p<INF>1</INF>p<INF>2</INF>p<INF>3</INF>p<INF>4</INF> is reasonably
large, as certainly occurs in the unmitigated situation.
We believe that assertion is inappropriate because it mixes units,
first assuming a per-fruit probability, then a per-box probability. We
were consistent throughout the risk assessment and used per-box
probabilities for each node.
Comment: To correctly model the mitigated situation, more
information should be presented about exactly what happens when citrus
black spot or sweet orange scab is detected on fruit destined for the
United States. Is the entire shipment prohibited from entering the
United States? What about other shipments en route from the same grove?
These do not appear to have been accounted for in the probability
distributions for the risk assessment. The proposed regulations require
that the grove be removed from the export program for the duration of
the growing season if citrus black spot or sweet orange scab is
detected upon any required inspection, including inspection at the port
of first arrival. Would the removal of such groves from the export
program affect any of the distributions in the risk assessment? It
certainly affects the structure of the overall probability model.
Response: As described in the proposed rule and noted by the
commenter, should any of these diseases be detected on fruit destined
for the United States, the entire shipment will be rejected and the
grove will be eliminated from the program for the remainder of the
shipping season. These events--the rejection of shipments and the
elimination of groves--can be viewed as successful applications of the
systems approach and, as such, contribute to the risk reductions
estimated in our risk assessment. Because the probabilities assigned to
each node that represents a risk mitigation step relate directly to a
``failure'' of that particular step (e.g., pest not detected, pest
survives treatment), our explicit focus was on failures rather than on
successful applications of the systems approach. Those successes were,
however, inherently reflected and accounted for in the appropriate
probability distributions in the risk assessment.
Comment: APHIS makes no attempt to account for the number of fruit
in a box that are affected or for the number of pests affecting each
fruit. Certainly, if several pieces of fruit in a given box were
infested with fruit flies, the probability of the pest establishing
itself in the United States as a result of the contaminated box would
be much higher than if only one fruit was infected, as is explicitly
acknowledged in section 8.e P8 of the risk assessment.
[[Page 37638]]
Because the ranges for these variables are large (ranging from zero to
the maximum number of fruit in a box and from zero to a large number of
pests per box), accounting for variability in the number of infested or
infected fruits per box and for the number of pests per fruit (or box)
could have a large impact on the results of the risk assessment.
Response: As stated in the risk assessment (section 8.e P1, p.29),
we considered the possibility that more than one fruit in a box might
be infested with fruit flies (``Specifically, this node represents the
probability of one or more individual fruit in a box being infested by
any of the four species of fruit flies.'').
However, because the likelihood that any individual fruit will be
infested is low (mode of distribution = 0.00009), and because the fruit
are mixed thoroughly prior to packing, the likelihood that multiple
fruit within a single box will be infested is considerably smaller than
0.00009. As indicated in the quote above, our estimates accounted for
this possibility.
Regarding multiple larvae, the most likely way (virtually the only
way) that one of these fruit fly species could become established as a
result of the importation of infested fruit is if there are multiple
larvae in a particular fruit. A reasonable consideration of this
situation leads to the conclusion that unless multiple larvae are
present, it would be nearly impossible for a breeding pair to form.
Thus, multiple larvae infesting a given fruit was the primary factor in
our estimate. In addition, it should also be remembered that this rule
will require all susceptible fruit to be treated according to a
treatment schedule with a documented efficacy of 99.9968 percent.
Comment: APHIS states, ``The nodes in our scenario (risk model)
represent independent events that must all take place before an
introduction can occur.'' However, it is not sensible to believe that
the eight stages considered in the APHIS risk assessment are truly
independent, or that the diagram (Figure 2 of the risk assessment)
adequately represents the process of importation of citrus fruit. The
model used in the assessment, which consists solely of independent
stages, appears to have been selected to agree with APHIS's ``Detailed
Description of the PPQ Pathway-Initiated Qualitative Commodity Pest
Risk Assessment, Version 4.1'' for qualitative assessments. However,
these guidelines are incorrect, even for a qualitative risk assessment.
It may not be possible to construct such a linear sequence of steps to
adequately represent the movement of a commodity--a more complex
diagram may be necessary. Moreover, even if it is possible to construct
such a sequence of such steps, it is incorrect to make estimates
independently for each step. What is required are the conditional
probabilities for subsequent steps, based on the prior steps in the
sequence.
Response: We consider it completely reasonable, given the
parameters of the model, that all eight nodes are independent. Indeed,
the model was constructed with the express purpose of constructing a
model with independent nodes (events), and an expert review of the
model conducted by the Harvard Center for Risk Analysis reported in the
journal Risk Analysis (Gray et al., 1998) has validated our model and
its assumption of independence. Without specific details from the
commenter as to where and how dependencies might affect the model and
its outcome, it is not possible to address this comment in detail
except to repeat our statement that they are independent. Our model
provides a framework for estimating risk, and we (and others, as noted
above) believe the guidelines are valid. The model we selected has
proven itself over the years, and for several commodity/pest
combinations, to be an efficient means of estimating this type of risk.
While we acknowledge that there are alternative ways of estimating this
type of risk, we do not believe that using a different model would
result in a substantively different outcome.
The risk model (scenario) was not, as stated by the commenter,
offered to represent the process of importation of citrus fruit. The
process was explained in the proposed rule, and details of the proposed
risk mitigation program were listed in the risk assessment on pp. 26-
28. Nor was our risk scenario offered to represent each mitigation
measure in the proposed program; rather, it represents ``independent
events that must all take place before an introduction can occur.'' The
frequency of shipments/number of boxes (F1) and four of the eight nodes
(P4, P6-P8) are not affected by risk mitigation measures. P1 is
affected by standard and special pest control activities, P2 and P3
represent inspections for pests, and P5 represents a variety of
treatments depending on host and pest.
The commenter asserts that the model appears to have been selected
to agree with APHIS' guidance for performing qualitative risk
assessments, when in fact our baseline scenario (risk model) for these
risk assessments was developed before our qualitative process; the
qualitative process is based on the probabilistic scenario. The
commenter continues by stating: ``However, these guidelines are
incorrect, even for a qualitative risk assessment. It may not be
possible to construct such a linear sequence of steps to adequately
represent the movement of a commodity--a more complex diagram may be
necessary. Moreover, even if it is possible to construct such a
sequence of such steps, it is incorrect to make estimates independently
for each step.'' As stated above, the scenario was never intended to
represent movement of a commodity. As we explained in the risk
assessment, the nodes in our scenario represent independent events that
must all take place before an introduction can occur. Regarding the
commenter's statement that ``a more complex diagram may be necessary,''
we disagree. We believe that the events described in the risk model are
necessary and sufficient for pest introduction. The commenter also
states that ``What is required are the conditional probabilities for
subsequent steps, based on the prior steps in the sequence.''
Conditional probabilities would be inappropriate because the nodes are
independent.
Comment: APHIS' failure to account for human error and failure
modes that could result in skipping one or more of the eight stages in
its model is the most significant structural error in the assessment.
It is inconceivable that 1.2 million boxes per year of fruit could all
be treated forever according to the risk mitigation program without a
single mistake. Some stages of the systems approach are likely to be
omitted at times through negligence, accident, or design. Since some of
the steps greatly reduce pest survival (assuming the pest traverses the
step), even small probabilities for omission of such steps must be
included in the analysis. APHIS should have used fault tree analysis in
its assessment to evaluate the areas where failure can occur.
Response: All of the estimates for model inputs that are affected
by human activities (P1 through P4) are based at least in part on a
consideration of human error. For example, the most obvious reason that
a pest would not be detected at harvest (P2) or during packing (P3)
would be an insufficient inspection (i.e., human error). The
possibility of human error in fungicide applications is considered in
P1 and the failure of post-harvest treatments is considered in P4. The
other nodes are based either on marketing decisions (F1, P6) or pest
biology (P5, P7-8). We do not believe that fault tree analyses are
required in areas where failure can occur, as all of the nodes in our
model that have a human component represent a ``failure'' of the
system.
[[Page 37639]]
Comment: APHIS attempts to account for human error in some stages
of the model, but ignores it in other stages. When constructing a
distribution for sweet orange scab infection rates, APHIS claims to
account for the nature of the sweet orange scab fungus and the
possibility of human error in fungicide applications. However, it is
impossible for us to review the appropriateness of the distribution
constructed by APHIS' experts because APHIS does not describe in detail
how it accounts for the possibility of human error.
Response: The direct data we had available when preparing this
distribution were limited, and we explicitly acknowledged that in the
risk assessment. As noted by the commenter, we recognized that human
error (e.g., the improper or incomplete application of the fungicidal
sprays) would limit the effectiveness of this aspect of the program.
However, there are no objective criteria that one can use to move from
recognizing that there is the possibility of human error in fungicide
application to an estimate of how much human error there is likely to
be. There is no database that can be used to predict the frequency or
severity of human error in fungicide applications, and little or no
direct experimental evidence exists from which one can derive estimates
for the effects of human error. We recognized, therefore, that there
would necessarily be a large element of uncertainty in our estimates of
potential human error, which we considered along with the biology of
sweet orange scab in estimating disease incidence; that uncertainty is
evident in the fact that the experts agreed that the disease incidence
might range from 0.1 to 30 percent. We believe that the distribution we
constructed appropriately accounts for the uncertainty in our estimates
of the effects of human error.
Comment: APHIS takes no account of the possibility of failure modes
associated with the cold treatment for fruit flies. Treatment schedules
for fruit flies are based on a demonstrated survival rate of 0.00003.
This survival rate is the mode of the distribution selected to
characterize the probability that fruit flies will survive cold
treatment. If any boxes of fruit escape cold treatment (as will almost
certainly happen for a small fraction of the 1.2 million boxes), the
chance of fruit fly survival increases dramatically (by a factor of
33,000) for those boxes. Failure modes could easily be incorporated
into the analysis by adding a Bernoulli function or a Dirac delta
function to steps that could accidentally be skipped.
Response: The process of research and development for establishing
commodity treatments is well documented in the scientific literature.
Before any treatment is accepted, confirmatory tests must be completed
to simulate treatments under actual treatment conditions. When fruit
are treated, monitoring devices are placed to record the conditions of
the treatment. Before fruit are allowed entry, the treatment record is
verified to ensure that the fruit were treated according to the
treatment schedule. If the fruit were not treated according to the
schedule, they would be denied entry. This requirement directly
addresses the possibility of failures in the application of the cold
treatment.
Comment: The principal failure of the risk assessment with respect
to the probability distributions is the failure to cite any credible
data underlying their selection, and the failure to provide any
documentation on their derivation. Where some studies are cited to
provide a basis for the derivation, APHIS provides only vague
references. Examination of the rulemaking record turns up summary data
from various studies in Argentina that may correspond to those
references, but there is no way a reviewer can be absolutely certain.
No analyses of the studies are provided or referenced in the risk
assessment or the rulemaking record, so the basis of the risk
assessment estimates for mean values and variability or uncertainty
cannot be evaluated. It is clear, however, that the entire risk
assessment fails to distinguish variability and uncertainty.
Response: The probability density functions (PDF's) used by APHIS
in the Argentine citrus and other assessments are what Hoffman and
Kaplan refer to as ``subjective probability distributions'' in a recent
article in Risk Analysis, An International Journal (``Beyond the Domain
of Direct Observation: How to Specify a Probability Distribution that
Represents the `State of Knowledge' about Uncertain Inputs,'' Vol. 19,
No. 1, 1999, pp.131-134). They are subjective precisely because no
direct evidence existed to allow construction of a objective
probability distribution. As emphasized by Hoffman and Kaplan, this is
the norm in probabilistic risk assessment.
In no case were data available that could be used to directly
specify a PDF, that is, data that represented results of studies that
provided an estimate of the parameter with associated information
regarding the range of values, variability or uncertainty in the data,
and the shape of the distribution. ``Risk assessment does not
legitimately focus on filling the information gaps, but rather on
making a decision in the absence of information,'' (Orr, et al., 1994).
Although doing a risk assessment under these conditions may be
considered unacceptable by non-practitioners, the only way to complete
this type (and most types) of risk assessment is to make the best
estimate possible based on whatever indirect information is available.
In most cases, there were no indirect data either (results of
experiments conducted to test a particular hypothesis). However, we
relied on the best available scientific information and, in virtually
every case, reliable data and information existed that related to the
parameter for which an estimate was needed. For example, although there
may be no data per se regarding the likelihood that Xanthomonas
axonopodis would be ``. . . able to complete disease cycle'' (P8)
following entry into the United States on fruit for consumption, there
is a wealth of scientifically valid data and information, and
conclusions in scientific papers, that demonstrate that the likelihood
is extremely low. Although we did not, in all cases, explicitly link
sources of information to the PDF's in which the information was used,
our knowledge of each of the insect pests and diseases is summarized in
the pest data sheets contained in the risk assessment's appendices and
our sources of information are cited in each pest data sheet and in
section III (References) of the risk assessment. Additional information
regarding the construction of each of the distributions is contained in
the addendum to the risk assessment that is available from the person
listed under FOR FURTHER INFORMATION CONTACT.
Regarding the statement that ``it is clear, however, that the
entire risk assessment fails to distinguish variability and
uncertainty,'' we call the commenter's attention to section 8.c where
we stated:
We were uncertain about the input values for the likelihood model.
This is typical for risk assessments. Uncertainty in the estimated
values may arise from (among other things):
<bullet> natural variation over time
<bullet> natural variation from place to place
<bullet> data gaps or unconfirmed data
<bullet> relationships among multiple components in a node.
This statement documents the fact that we considered both
variability and uncertainty. While it is true that we did not model
variability or uncertainty separately, doing so is not a common
practice, and this approach is useful only in certain circumstances.
While this approach may provide more detailed information, it is not a
given
robop...@us.govnews.org
Posting-number: Volume 65, Issue 116, Page 37607, Part 1
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As shown in Table 9, both producer losses and consumer gains during
this final period would be slightly less than during the previous two
stages, as Argentine imports would compete with the entire domestic
fresh supply. Producer losses in this scenario range between $21.35
million and $35.52 million, while consumer gains are between $21.74
million and $36.59 million. The net benefits would thus be between
$390,000 and $1.07 million.
One of the commenters who responded to our proposed rule stated
that in Argentina, 30 percent of lemon acreage is due to begin bearing
during the next 5 years, thus annual production of lemons will increase
significantly. This commenter reported that estimated lemon production
increased 240 million pounds from 1996 to 1997 and concluded that
within 5 years, Argentine citrus exporters, with an established
distribution network, could very easily export 100 to 200 million
pounds or more of fresh lemons to the United States during the summer
months, a much larger export level than was considered in the proposed
rule's economic analysis.
With regard to current increases and potential suitable land for
future expansion of lemon groves in Argentina, both planted acres and
harvested acres have increased from their 1996 levels. Planted acreage
increased from 76,763 acres to 102,698 acres in 1998, while harvested
acreage increased from 69,854 acres to 95,095 acres. As can be seen,
harvested acres accounted for about 92.6 percent of the planted acreage
in 1998. For 1999, acres planted are forecasted to increase to 106,210
acres, while harvested acres are forecasted to decline to 93,860 acres
as older groves are replaced by younger, non-fruit-bearing trees. Over
90 percent of the planted acreage is being harvested, and about 5
percent of new plantings are replacement plantings. If these expansions
continue and if weather conditions are favorable, Argentina will have a
much larger potential to export more fresh lemons to all countries,
[[Page 37665]]
including the United States. (USDA/FAS, Argentina Citrus Annual Reports
for 1997 [AR7043], 1998 [AR8032], and 1999 [AR9034], U.S. Embassy,
Buenos Aires, Argentina; Randall J. Hager, Agricultural Attache, Office
of Agricultural Affairs, U.S. Embassy, Buenos Aires, August 1999,
personal communication; and Mariano Ripari, Agricultural Attache,
Embassy of Argentina, Washington DC, August 1999, personal
communication).
Whether this expansion will continue, and how it will affect the
United States, depends not only on the availability of suitable land in
Argentina and the capital to convert that land to lemon groves, but
also on many other factors such as production costs, relative world
prices for fresh lemons, U.S. prices, the exchange rates for major
currencies, changes in consumer taste for fresh lemons, growth in the
demand for fresh lemons in other countries that are already importing
from Argentina, the opening of other potential markets (e.g., new
markets for Argentine lemons are opening in the Far East), and the
profitability of alternative land use. Since inclement weather can
affect both the quantity and quality of fresh lemons, there is added
uncertainty in predicting Argentina's fresh lemon export capacity. For
example, although production increased from about 1,905 million pounds
in 1997 to 2,260 million pounds in 1998, this did not translate to
large export levels for fresh lemons. Instead, exports declined from
388 million pounds to 344 million pounds, as fresh lemons were diverted
for processing due to rainy weather that caused poor quality.
Table 10 shows an import of 100 million pounds of fresh lemon to
the United States would result in price decline of about 26 percent and
producer loss of about $80 million. However, consumer benefit would be
about $86 million dollars, yielding a net benefit of about $5.57
million. We do not expect this level of lemon imports from Argentina to
be realized.
Table 10.--Impact in the United States of Larger Argentine Lemon Exports
to the United States
[Price elasticity of demand is -0.44 and price elasticity of supply is
0.09]
------------------------------------------------------------------------
------------------------------------------------------------------------
Potential exports to the United States (millions of pounds) *100
Percent change in price.................................... -25.92
Percent change in quantity**............................... -2.33
Decrease in producer surplus (millions of dollars)......... -80.19
Increase in consumer surplus (millions of dollars)......... 85.76
------------
Total surplus (millions of dollars).................... 5.57
------------------------------------------------------------------------
*Less than perfectly inelastic supply.
**This decrease in quantity may be due to diversion of fresh lemons to
the processing sector as the price of fresh lemons declines.
Increased ability to export will translate to sales only if there
is a comparable market demand for fresh lemons. Over the last several
years, per capita consumption (between 2.54 and 2.90 pounds per person)
has remained stable, with very small variability (a mean of 2.7 pounds
per person and a standard deviation of 0.12 pounds per person). U.S.
consumption of fresh lemons over the last 3 years has declined from
766.3 million pounds (peak amount in 1995/96) to 747.9 million and
675.8 million pounds in 1996/97 and 1997/98, respectively (USDA/ERS,
``Fruit and Tree Nuts: Situation and Outlook Report,'' October 1999,
p.74). Most available estimates for the price elasticity of demand for
fresh lemon are below -0.5, implying that the demand for fresh lemons
is price inelastic. This means that for every 1 percent decrease in
their price, the demand for fresh lemons would increase by less than
0.5 percent. Given an estimated price elasticity of -0.44, a 100-
million-pound increase in supply of fresh lemons would require a price
decrease of about 26 percent. In other words, for a large quantity of
fresh lemons to be absorbed, the price of fresh lemons has to decrease
substantially. If 100 million or more pounds of fresh lemons were to be
imported from Argentina, the negative effect on domestic producers
would be much larger than predicted under the importation scenario of
44 million pounds. Consumer benefits would still outweigh producer
losses. Since such a large influx of fresh lemons would require a large
price decline to be absorbed, it would not be profitable for Argentina
to export fresh lemons in such large quantities to the United States.
Oranges
Using a 5-year average (1992/93 through 1996/97) of U.S.
consumption, production plus imports minus exports, we estimated U.S.
domestic consumption of oranges to be 3,479 million pounds. The average
price is $0.40 per pound. As with lemons, there are very few published
elasticity estimates available. The two studies most often referred to
are by Huang (1993) and Thompson et al. (1990) and relate to oranges
and grapefruit. Huang provides estimates both for Marshallian and
Hicksian demand systems. The results of the Marshallian demand system
are reported and used here--a demand elasticity of -0.849 for oranges.
Thompson, et al. estimate -0.719 for the demand elasticity for oranges.
A recent study showed that the elasticity of supply for California
oranges was 0.149 (Villezca-Becerra and Shumway 1992). In our analysis,
we use the -.849 estimate made by Huang for the elasticity of demand
and assume an elasticity of supply equal to 0.149.
Similar to lemons, our estimate for Argentine orange exports to the
United States are based on growth rates in Argentina's fresh orange
exports to the rest of the world. As above, a simple semi-log model was
used to estimate the growth rate of orange exports between 1985 and
1996. The results show that orange exports increased at the rate of 4.1
percent during that period. Using 1992-1996 average exports from the
Argentina, 171 million pounds, as a baseline number and assuming the
share of exports from the eligible Argentine States would continue to
be 26.59 percent, the total expected increase in exports would be 1.86
million pounds (171 x 0.2659 x .041) or, rounding, 2 million
pounds.
Table 11 reports the potential effects of orange imports from
Argentina during the first, second, and third stages of the import
program. We believe the price differential between U.S. and Argentine
oranges illustrated in Table 6 suggests that a lower proportion of
Argentine orange exports will be diverted to the United States.
Therefore, we assume a 20 percent diversion of the 2 million pounds of
the expected increase in Argentine exports, or 400,000 pounds. Table 11
shows that price decreases as the volume of imported oranges increases,
given domestic supply in the approved States during every stage.
[[Page 37666]]
Table 11.--The Importation of Fresh Oranges from Argentina to Approved
States for Stages 1 through 3, assuming 20 percent of average Argentine
orange export diverted to the U.S. market
------------------------------------------------------------------------
Stage
--------------------------------------
1 2 3
------------------------------------------------------------------------
Imports (millions of pounds)..... 0.4 0.4 0.4
Percent change in price.......... -0.04 -0.03 -0.012
Percent change in quantity....... -0.003 -0.003 -0.002
Decrease in producer surplus -0.3019 -0.3019 -0.16032
(millions of dollars)...........
Increase in consumer surplus 0.3019 0.3019 0.16033
(millions of dollars)...........
Net benefit (millions of dollars) 0.0000 0.0000 0.00001
------------------------------------------------------------------------
Note: The utilized supply for Stage 1 is 2,089 million pounds for
approved States; for Stage 2 it is 2,518 million pounds.
Consumer gains in every stage are approximately equal to producer
losses.
Grapefruit
Using a 5-year average (1992/93 through 1996/97) of U.S.
consumption, production plus imports minus exports, we estimated U.S.
domestic consumption of grapefruit to be 1,602 million pounds. The
average price is $0.29 per pound. As with lemons, there are very few
published elasticity estimates available. The two studies most often
referred to are by Huang (1993) and Thompson et al. (1990) and relate
to oranges and grapefruit. Huang provides estimates both for
Marshallian and Hicksian demand systems. The results of the Marshallian
demand system are reported and used here--a demand elasticity of -0.455
for grapefruit.
Thompson, et al. estimate -0.523 for the demand elasticity for
grapefruit. A recent study showed that the elasticity of supply for
California grapefruit was 0.409 (Villezca-Becerra and Shumway 1992). In
our analysis we use the -0.455 estimate made by Huang for the
elasticity of demand and assume an elasticity of supply equal to 0.409.
Similar to lemons and oranges, our estimate for Argentine
grapefruit exports to the United States are based on growth rates in
Argentina's fresh grapefruit exports to the rest of the world. As
above, a simple semi-log model was used to estimate the growth rate of
grapefruit exports between 1985 and 1996. The results show that
grapefruit exports increased at the rate of 1 percent during that
period. Using 1992-1996 average exports from the Argentina, 79.72
million pounds, as a baseline number and assuming the share of exports
from the eligible Argentine States would continue to be 51.22 percent,
the total expected increase in exports would be 0.41 million pounds
(79.72 x 0.5122 x 0.01).
Given the price advantage possessed by U.S. producers of grapefruit
(see Table 6), we believe that it is highly unlikely that Argentine
grapefruit will be marketed in the United States.
However, if we perform an analysis of the impact of grapefruit
imports similar to the analysis done for oranges and lemons, we find
that there is not a significant effect on either U.S. producers or
consumers. On the basis of the growth rate of grapefruit production in
Argentina, which was less than 1 percent, the maximum that could be
diverted would be about 410,000 pounds. This amount, when compared to
about 1,603 million pounds of domestic supply of fresh grapefruit in
the United States, is very small. As a result, price would decrease by
only about 0.03 percent with 100-percent diversion in Stage 3.
Producers losses and consumer gains both would be around $137,600,
yielding a net benefit of zero.
Conclusion
Overall, the estimated net economic effects of this rule are
positive. There is a direct relationship between producer losses and
consumer gains on the one hand and the quantity of imports on the other
hand. Therefore, the larger the share of imports from Argentina,
relative to U.S. domestic supply, the larger the U.S. producer losses
and the larger the U.S. consumer gains. In all cases, consumer gains
are equal to or slightly outweigh grower losses.
As seen in Tables 7 through 11, the entry of fresh citrus fruits
from Argentina into U.S. markets would induce producer losses and
consumer gains. The greatest effect would be due to importation of
lemons because the price differential between domestic fresh lemons and
Argentine lemons may be largest. The expected lemon imports from
Argentina would represent a larger proportion of the U.S. domestically
available fresh lemon volume compared to that for fresh oranges and
grapefruit.
Overall, considering all three stages of the import program, fresh
lemon prices could potentially decrease between 6.84 percent and 19
percent. Producers would possibly lose between $21.35 million and
$36.96 million, while consumers would potentially gain between $21.74
million and $38.83 million annually as the result of importing fresh
lemons from Argentina, yielding a net benefit of between $390,000 and
$1.876 million. In all cases, consumer gains slightly outweigh grower
losses.
The extent of any actual decrease in prices would depend to a great
degree upon the size of the price elasticity of demand, the magnitude
of the change in supply, and the size of the baseline price. For lower
price elasticities, both losses and gains would be higher. Since fresh
fruit exports from Argentina, especially of oranges and grapefruit, are
not expected to be large, they are not expected to change citrus fruit
production and consumption patterns in the United States.
Because Argentina's peak season of production complements the U.S.
low season of production (particularly for oranges and grapefruit) and
vice versa, this rule should have a positive effect for consumers. U.S.
prices during the months of June through September are higher than the
annual average. The effect would vary by commodity, with the largest
effect on lemon prices. As a result of the highest expected additional
fresh lemon supply, the average lemon price in the United States would
decrease by as much as 19 percent (in Stage 1), from 43 cents per pound
to about 34.83 cents per pound. Orange prices would decline by as much
as 0.04 percent (in Stage 1), from 40 cents per pound to 39.98 cents
per pound. The effect on grapefruit prices is even more insignificant.
In addition, it is important to note that the analysis implicitly
assumes the worst-case scenario because the partial equilibrium
analysis does not allow for substitution among producers. If the price
of fresh citrus fruits decreases significantly, then the producers may
choose to channel their products to overseas markets or to processing
[[Page 37667]]
markets. Under those scenarios, the decrease in prices expected to
result from this rule would be less than that estimated in this
analysis, resulting in less of a decrease in producer surplus.
This rule would have a net positive effect on the overall economy,
since consumer benefits would be slightly higher than producer losses.
The increased potential for trade and facilitation of flow of goods
will benefit the welfare of both countries. These trading relationships
benefit numerous sectors in the U.S. national economy. Increased trade
in these sectors have dual benefits. Those employed are also consumers
of fresh citrus fruit. Since fresh citrus fruits are normal goods, with
positive income elasticities, increased jobs, outputs, and income in
those sectors can also mean increased consumption of citrus products.
The only significant alternative to this rule would be to make no
changes in the regulations; i.e., to continue to prohibit the
importation of grapefruit, lemons, and oranges from Argentina. We have
rejected that alternative because we believe that Argentina has
demonstrated that the citrus-growing areas of the States of Catamarca,
Jujuy, Salta, and Tucuman are free from citrus canker and because we
believe that the systems approach offered by Argentina to prevent the
introduction of other plant pests reduces the risks posed by the
importation of grapefruit, lemons, and oranges to a negligible level.
Under these circumstances, the Administrator of the Animal and
Plant Health Inspection Service has determined that this action will
not have a significant economic impact on a substantial number of small
entities.
Executive Order 12988
This final rule allows the importation of grapefruit, lemons, and
oranges from Argentina under certain conditions. State and local laws
and regulations regarding grapefruit, lemons, and oranges imported
under this rule are preempted while the fruit is in foreign commerce.
Grapefruit, lemons, and oranges are generally imported for immediate
distribution and sale to the consuming public and will remain in
foreign commerce until sold to the ultimate consumer. The question of
when foreign commerce ceases in other cases must be addressed on a
case-by-case basis. No retroactive effect will be given to this rule,
and this rule does not require administrative proceedings before
parties may file suit in court challenging this rule.
National Environmental Policy Act
An environmental assessment and finding of no significant impact
have been prepared for this rule. The assessment provides a basis for
the conclusion that the importation of grapefruit, lemons, and oranges
under the conditions specified in this rule will not present a risk of
introducing or disseminating plant pests and would not have a
significant impact on the quality of the human environment. Based on
the finding of no significant impact, the Administrator of the Animal
and Plant Health Inspection Service has determined that an
environmental impact statement need not be prepared.
The environmental assessment and finding of no significant impact
were prepared in accordance with: (1) The National Environmental Policy
Act of 1969 (NEPA), as amended (42 U.S.C. 4321 et seq.), (2)
regulations of the Council on Environmental Quality for implementing
the procedural provisions of NEPA (40 CFR parts 1500-1508), (3) USDA
regulations implementing NEPA (7 CFR part 1b), and (4) APHIS' NEPA
Implementing Procedures (7 CFR part 372).
Copies of the environmental assessment and finding of no
significant impact are available for public inspection at USDA, room
1141, South Building, 14th Street and Independence Avenue SW.,
Washington, DC, between 8 a.m. and 4:30 p.m., Monday through Friday,
except holidays. Persons wishing to inspect copies are requested to
call ahead on (202) 690-2817 to facilitate entry into the reading room.
In addition, copies may be obtained by writing to the individual listed
under FOR FURTHER INFORMATION CONTACT.
Paperwork Reduction Act
In accordance with section 3507(d) of the Paperwork Reduction Act
of 1995 (44 U.S.C. 3501 et seq.), the information collection or
recordkeeping requirements included in this final rule have been
approved by the Office of Management and Budget (OMB). The assigned OMB
control number is 0579-0134.
List of Subjects
7 CFR Part 300
Incorporation by reference, Plant diseases and pests, Quarantine.
7 CFR Part 319
Bees, Coffee, Cotton, Fruits, Honey, Imports, Incorporation by
reference, Nursery Stock, Plant diseases and pests, Quarantine,
Reporting and recordkeeping requirements, Rice, Vegetables.
Accordingly, we are amending title 7, chapter III, of the Code of
Federal Regulations as follows:
PART 300--INCORPORATION BY REFERENCE
1. The authority citation for part 300 continues to read as
follows:
Authority: 7 U.S.C. 150ee, 154, 161, 162 and 167; 7 CFR 2.22,
2.80, and 371.2(c).
2. In Sec. 300.1, paragraph (a), the introductory text is revised
to read as follows:
Sec. 300.1 Materials incorporated by reference.
(a) Plant Protection and Quarantine Treatment Manual. The Plant
Protection and Quarantine Treatment Manual, which was reprinted
November 30, 1992, and includes all revisions through May 2000, has
been approved for incorporation by reference in 7 CFR chapter III by
the Director of the Office of the Federal Register in accordance with 5
U.S.C. 552(a) and 1 CFR part 51.
* * * * *
PART 319--FOREIGN QUARANTINE NOTICES
3. The authority citation for part 319 continues to read as
follows:
Authority: 7 U.S.C. 150dd, 150ee, 150ff, 151-167, 450, 2803, and
2809; 21 U.S.C. 136 and 136a; 7 CFR 2.22, 2.80, and 371.2(c).
Sec. 319.28 [Amended]
4. In Subpart--Citrus Fruit, Sec. 319.28 is amended as follows:
a. In paragraph (a)(1), by adding the words ``Argentina (except for
the States of Catamarca, Jujuy, Salta, and Tucuman, which are
considered free of citrus canker),'' immediately after the word
``Seychelles,''.
b. In paragraph (a)(2), by adding the words ``(except as provided
by Sec. 319.56-2f of this part)'' immediately after the word
``Argentina''.
c. In paragraph (a)(3), by adding the words ``(except for the
States of Catamarca, Jujuy, Salta, and Tucuman, which are considered
free of Cancrosis B)'' immediately after the word ``Argentina''.
Sec. 319.56a [Amended]
5. In Sec. 319.56a, paragraph (e), the first sentence is amended by
removing the words ``and 319.56-2f to 319.56-2m, inclusive,'' and
adding the words ``, 319.56-2e, 319.56-2g, 319.56-2k, 319.56-2l, and
319.56-2p'' in their place.
6. In Subpart Fruits and Vegetables, a new Sec. 319.56-2f is added
to read as follows:
[[Page 37668]]
Sec. 319.56-2f Administrative instructions governing importation of
grapefruit, lemons, and oranges from Argentina.
Fresh grapefruit, lemons, and oranges may be imported from
Argentina into the continental United States (the contiguous 48 States,
Alaska, and the District of Columbia) only under permit and only in
accordance with this section and all other applicable requirements of
this subpart.
(a) Origin requirement. The grapefruit, lemons, or oranges must
have been grown in a grove located in a region of Argentina that has
been determined to be free from citrus canker. The following regions in
Argentina have been determined to be free from citrus canker: The
States of Catamarca, Jujuy, Salta, and Tucuman.
(b) Grove requirements. The grapefruit, lemons, or oranges must
have been grown in a grove that meets the following conditions:
(1) The grove must be registered with the citrus fruit export
program of the Servicio Nacional de Sanidad y Calidad Agroalimentaria
(SENASA).
(2) The grove must be surrounded by a 150-meter-wide buffer area.
No citrus fruit grown in the buffer area may be offered for importation
into the United States.
(3) Any new citrus planting stock used in the grove must meet one
of the following requirements:
(i) The citrus planting stock originated from within a State listed
in paragraph (a) of this section; or
(ii) The citrus planting stock was obtained from a SENASA-approved
citrus stock propagation center.
(4) All fallen fruit, leaves, and branches must be removed from the
ground in the grove and the buffer area before the trees in the grove
blossom. The grove and buffer area must be inspected by SENASA before
blossom to verify that these sanitation measures have been
accomplished.
(5) The grove and buffer area must be treated at least twice during
the growing season with an oil-copper oxychloride spray. The timing of
each treatment shall be determined by SENASA's expert system based on
its monitoring of climatic data, fruit susceptibility, and the presence
of disease inoculum. The application of treatments shall be monitored
by SENASA to verify proper application.
(6) The grove and buffer area must be surveyed by SENASA 20 days
before the grapefruit, lemons, or oranges are harvested to verify the
grove's freedom from citrus black spot (Guignardia citricarpa) and
sweet orange scab (Elsinoe australis). The grove's freedom from citrus
black spot and sweet orange scab shall be verified through:
(i) Visual inspection of the grove and buffer area; and
(ii) The sampling of 4 fruit from each of 298 randomly selected
trees from each grove and buffer area covering a maximum area of 800
hectares. If the area to be sampled exceeds 800 hectares, SENASA must
contact APHIS for APHIS' determination as to the number of trees to be
sampled. The sampled fruit must be taken from those portions of the
trees that are mostly likely to have infected, symptomatic fruit (i.e.
near the outer, upper part of the canopy on the sides of the tree that
receive the most sunlight). The sampled fruit must be held in the
laboratory for 20 days at 27 deg.C, 80 percent relative humidity, and
in permanent light to promote the expression of symptoms in any fruit
infected with citrus black spot.
(c) After harvest. After harvest, the grapefruit, oranges, or
lemons must be handled in accordance with the following conditions:
(1) The fruit must be moved from the grove to the packinghouse in
field boxes or containers of field boxes that are marked to show the
SENASA registration number of the grove in which the fruit was grown.
The identity of the origin of the fruit must be maintained.
(2) During the time that any grapefruit, lemons, or oranges from
groves meeting the requirements of paragraph (b) of this section are in
the packinghouse, no fruit from groves that do not meet the
requirements of paragraph (b) of this section may enter the
packinghouse. A packinghouse technician registered with SENASA must
verify the origin of all fruit entering the packinghouse.
(3) After arriving at the packinghouse, the fruit must be held at
room temperature for 4 days to allow bruises or other fruit damage to
become apparent.
(4) After the 4-day holding period, bruised or damaged fruit must
be culled and the fruit must be inspected by SENASA to verify its
freedom from citrus black spot and sweet orange scab. The fruit must
then be chemically treated as follows:
(i) Immersion in sodium hypochlorite (chlorine) at a concentration
of 200 parts per million for 2 minutes;
(ii) Immersion in orthophenilphenate of sodium;
(iii) Spraying with imidazole; and
(iv) Application of 2-4 thiazalil benzimidazole and wax.
(5) Before packing, the treated fruit must be individually labeled
with a sticker that identifies the packinghouse in which they were
packed and must be inspected by SENASA to verify its freedom from
citrus black spot and sweet orange scab and to ensure that all stems,
leaves, and other portions of plants have been removed from the fruit.
(6) The fruit must be packed in clean, new boxes that are marked
with the SENASA registration number of the grove in which the fruit was
grown and a statement indicating that the fruit may not be distributed
in Hawaii, Guam, the Northern Mariana Islands, Puerto Rico, the U.S.
Virgin Islands, or in any State (each of which must be individually
listed) into which the distribution of the fruit is prohibited pursuant
to paragraph (g)(1) or (g)(2) of this section.
(d) Phytosanitary certificate. Grapefruit, lemons, and oranges
offered for entry into the United States from Argentina must be
accompanied by a phytosanitary certificate issued by SENASA that states
the grapefruit, lemons, or oranges were produced and handled in
accordance with the requirements of paragraphs (a), (b), and (c) of
this section and that the grapefruit, lemons, or oranges are apparently
free from citrus black spot and sweet orange scab.
(e) Cold treatment. Due to the presence in Argentina of
Mediterranean fruit fly (Medfly) (Ceratitis capitata) and fruit flies
of the genus Anastrepha, grapefruit, lemons (except smooth-skinned
lemons), and oranges offered for entry from Argentina must be treated
with an authorized cold treatment listed in the Plant Protection and
Quarantine Treatment Manual, which is incorporated by reference at
Sec. 300.1 of this chapter. The cold treatment must be conducted in
accordance with the requirements of Sec. 319.56-2d of this subpart.
(f) Disease detection. If, during the course of any inspection or
testing required by this section or Sec. 319.56-6 of this subpart, or
at any other time, citrus black spot or sweet orange scab is detected
on any grapefruit, lemons, or oranges, APHIS and SENASA must be
notified and the grove in which the fruit was grown or is being grown
shall be removed from the SENASA citrus export program for the
remainder of that year's growing and harvest season, and the fruit
harvested from that grove may not be imported into the United States
from the time of detection through the remainder of that shipping
season.
(g) Limitations on distribution. The distribution of the
grapefruit, lemons, and oranges is limited to the continental United
States (the 48 contiguous States, Alaska, and the District of
Columbia.). In addition, during the 2000 through
[[Page 37669]]
2003 shipping seasons, the distribution of the grapefruit, lemons, and
oranges is further limited as follows:
(1) During the 2000 and 2001 shipping seasons, the fruit may be
distributed in all areas of the continental United States except
Alabama, Arizona, Arkansas, California, Colorado, Florida, Georgia,
Louisiana, Mississippi, Nevada, New Mexico, Oklahoma, Oregon, Texas,
and Utah.
(2) During the 2002 and 2003 shipping seasons, the fruit may be
distributed in all areas of the continental United States except
Arizona, California, Florida, Louisiana, and Texas.
(3) For the 2004 shipping season and beyond, the fruit may be
distributed in all areas of the continental United States.
(h) Ports of entry. The grapefruit, lemons, and oranges may enter
the United States only through a port of entry located in a State where
the distribution of the fruit is authorized pursuant to paragraph (g)
of this section.
(i) Repackaging. If any grapefruit, lemons, or oranges are removed
from their original shipping boxes and repackaged, the stickers
required by paragraph (c)(5) of this section may not be removed or
obscured and the new boxes must be clearly marked with all the
information required by paragraph (c)(6) of this section.
(Approved by the Office of Management and Budget under control
number 0579-0134)
7. Section 319.56-2i, including the section heading, is revised to
read as follows:
Sec. 319.56-2i Administrative instructions prescribing treatments for
mangoes from Central America, South America, and the West Indies.
(a) Authorized treatments. Treatment with an authorized treatment
listed in the Plant Protection and Quarantine Treatment Manual will
meet the treatment requirements imposed under Sec. 319.56-2 as a
condition for the importation into the United States of mangoes from
Central America, South America, and the West Indies. The Plant
Protection and Quarantine Treatment Manual is incorporated by
reference. For the full identification of this standard, see Sec. 300.1
of this chapter, ``Materials incorporated by reference.''
(b) Department not responsible for damage. The treatments for
mangoes prescribed in the Plant Protection and Quarantine Treatment
Manual are judged from experimental tests to be safe. However, the
Department assumes no responsibility for any damage sustained through
or in the course of such treatment.
Done in Washington, DC, this 8th day of June 2000.
Bobby R. Acord,
Acting Administrator, Animal and Plant Health Inspection Service.
[FR Doc. 00-14851 Filed 6-9-00; 10:00 am]
BILLING CODE 3410-34-U
robop...@us.govnews.org
Posting-number: Volume 65, Issue 116, Page 37607, Part 1
[[Page 37656]]
Response: The only situation where goodness-of-fit statistics are
appropriate was for the distribution used to characterize fruit fly
survival with the cold treatment. We did not conduct goodness-of-fit
tests because they were completed as part of the scientific research
conducted during establishment of the treatment protocol.
Discuss the presence or absence of moderate to strong correlations
between input variables. The APHIS report assumes that each of the
eight steps in the model is independent from all other steps. It is
unlikely that the eight steps are truly independent. Whether or not
strong correlations exist, APHIS should discuss the possibility that
correlations exist and estimate the effects of such correlations on the
results of the analysis.
Response: We did consider the possibility of correlations among the
various nodes. As we reported in the risk assessment, we are confident
that the nodes are independent, given the model and values used. Our
analyses detected no correlations. Our conclusion that the nodes are
independent resulted from both prior and ad hoc considerations, as well
as model outputs.
Provide detailed information and a graph for each output
distribution. APHIS presents the mode, median, mean, and 95th
percentile of the output distributions for each pest under the baseline
import program and assuming the presence of a pest mitigation program.
APHIS does not provide a graph for any of the output distributions.
Response: We have frequently considered whether we should include
graphical representations of our output distributions. We have
repeatedly reached the conclusion that it is neither necessary nor
important to do so. In fact, we believe it could serve to obscure our
findings.
Perform probabilistic sensitivity analyses for all key inputs to
distinguish the effects of variability from the effects of uncertainty
in the inputs. APHIS does not perform any sensitivity analyses to
identify the inputs with the greatest contributions to the output
distribution. As discussed previously, APHIS makes no attempt to
distinguish the effects of variability from those of uncertainty.
Response: We always conduct sensitivity analyses as part of our
probabilistic risk modeling, and did so for the Argentine citrus risk
assessment; contrary to the commenter's assertion, those analyses did
indeed indicate those inputs that contributed the greatest amount of
uncertainty to the output. (Those analyses are part of the
documentation contained in the supplemental information that is
available from the person listed under FOR FURTHER INFORMATION
CONTACT.) A sensitivity analysis addresses the relationship between
variation in the input parameters and variation in the output.
Specifically, the analysis quantifies the degree of correlation between
variation in individual input parameters and the output parameter. The
value of these coefficients does not, however, indicate the amount of
uncertainty in an input parameter. Because of the type of model we used
(i.e., simple, linear, and multiplicative), the values represent the
magnitude of the uncertainty (as represented by the standard deviation
of the input distribution) relative to the mean of the input
distribution.
The commenter suggest that sensitivity analysis can be used to
distinguish the effects of variability from the effects of uncertainty
in the inputs, but we do not believe that is possible. When data are
available to allow analysts to distinguish variability from other
sources of uncertainty, variability and other forms of uncertainty can
be accounted for, and modeled, separately. This is accomplished by
having separate inputs for variability and other forms of uncertainty
in the input parameters. However, in this particular case (as in the
majority of probabilistic risk assessments), the available information
did not allow us to model variability separately from other sources of
uncertainty. A sensitivity analysis cannot change this fact and cannot
provide us with the ability to distinguish the effects of variability
from the effects of other sources of uncertainty.
In a simple, linear, multiplicative model of the type used in the
Argentine citrus assessment, the sensitivity analysis reflects little
more than the ``coefficient of variation'' of the input parameters. The
coefficient of variation is obtained by dividing the standard deviation
of the distribution by the mean. Parameters with relatively large
amounts of variation relative to their mean will have a relatively high
``sensitivity coefficient'' and will have a ``larger impact'' on the
output. Another way of stating this is that the output is most
sensitive to those input parameters about which the experts were most
uncertain. Thus, with this type of model, the sensitivity analysis
reflects uncertainty in the input parameters. Tables 7 through 10
reveal those parameters about which the experts were most uncertain
(P1, P5, P6, P7, P8, depending on pest and scenario); thus these are
the parameters that had the ``biggest impact'' on the output. The
values for both the standard deviation and the mean were provided in
the tables of input values (Tables 7 through 10), so the information
necessary to obtain the coefficient of variation was available in the
risk assessment. As the sensitivity analysis provides information that
is already available in Tables 7 through 10, we believed that little if
any additional information would have been provided by reporting the
sensitivity analysis in the risk assessment.
Regarding distinguishing the effects of variability and
uncertainty, as stated above, we have not encountered many situations
where we had sufficient, directly applicable data to provide separate
estimates for variability and other forms of uncertainty. Thus, to
conduct such an analysis would constitute overinterpretation of
available data.
Investigate the numerical stability of the output distribution.
APHIS does not investigate the numerical stability of either the
central moments of the output distribution (such as the mean and
standard deviation) or the tails of the output distribution.
Additionally, APHIS provides no discussion of the sensitivity of the
upper tails of the output distribution to the tails of the input
distributions. One option for investigating the numerical stability of
the output distribution is to calculate the uncertainty for the mean
and the 5th and 95th percentiles of the distribution. A second option
would be to perform a larger run (e.g., 50,000 iterations instead of
10,000) and to compare the distributions.
Response: The @Risk software we used automatically monitors
convergence ``to help monitor the stability of the output distributions
created during a simulation'' (@Risk software documentation: @Risk
Advanced Risk Analysis for Spreadsheets, 1997, Palisade Corporation,
Newfield, NY). That documentation states that the statistics monitored
on each output distribution are the average percent change in
percentile values (0 to 100 percent, in 5 percent steps), the mean, and
the standard deviation. Thus, we monitored the stability during all
simulations. Although @Risk simulations can be run with an ``automatic
shutoff'' option that is triggered when the output distribution has
reached stability, and despite the fact that the distributions reached
stability before completing all 10,000 iterations, we completed 10,000
iterations on each simulation. Prior to conducting the Argentine citrus
[[Page 37657]]
assessment, APHIS conducted informal investigations of the number of
simulations needed to reach stability with our simple, linear,
multiplicative models. We found that in some cases that running 1,000
iterations was not sufficient to reach stability, so we increased the
number of iterations in our simulations to 10,000. In the Argentine
citrus risk assessment, 10,000 iterations was found to be sufficient to
reach stability.
While considering out response to this comment, we re-ran our
simulations with 10,000 iterations (as done in the assessment) and then
with 50,000 iterations as suggested by the commenter. We used the same
random number generator seed. Results were the same with 10,000
iterations and not significantly different with 50,000 iterations. For
example, with the fruit fly program (as opposed to baseline)
simulation, the 95th percentile value with 10,000 iterations was 1.07
x 10<SUP>-5</SUP> (0.0000107) and with 50,000 iterations the 95th
percentile value was 1.08 x 10<SUP>-5</SUP> (0.0000108). Another
example with the same simulation is for the 90th percentile value, the
value with 10,000 iterations was 5.80 x 10<SUP>-6</SUP> (0.00000580)
and with 50,000 iterations was 5.61 x 10<SUP>-6</SUP> (0.00000561);
thus, the 90th percentile value (part of the upper tail) was lower
(less risk) with more iterations. Because the 90th and 95th percentile
values can be considered representative of the upper tail (upper
estimate for the likelihood of pest introduction), we offer this as an
indication of the stability of the upper tail. The purpose of
conducting a probabilistic assessment is to try a range of values to
see how the output changes. When the experts constructed the input
distributions, all necessary uncertainty regarding the inputs was
captured and the simulations included calculations based on the upper
tails of all nine distributions.
Present the name and statistical quality of the random number
generator used. APHIS does not present any information about the random
number generator used for the risk assessment. We assume that the
random number generator provided with @Risk was used in the assessment,
but as mentioned previously, the version of @Risk that was used in the
assessment is not specified. Even if this was the random number
generator used, more information should be provided, such that a reader
of the risk assessment could determine the quality of the random number
generator without purchasing @Risk.
Response: In section 8.d of the risk assessment, we stated that ``a
computer program randomly selects a value from each of the input
probability distributions. * * * We use the risk analysis computer
software package @Risk for Excel (Palisade Corp., Newfield, NY, USA) to
run our simulations.'' As noted previously, we used version 3.5c of
that program. We did not supply additional information regarding
@Risk's random number generator because we concluded that sufficient
information was provided in the @Risk documentation.
Discuss the limitations of the methods and the interpretation of
the results. APHIS offers neither a discussion of the limitations of
the methods used in the risk assessment nor an interpretation of the
results. APHIS does not acknowledge any sources of bias in the risk
assessment and does not discuss how additional research or measurements
might be able to improve the analysis.
Response: The purpose of our risk assessment was to inform a
decision regarding the enterability of commercial citrus from Argentina
under a specific risk mitigation program. We improve our risk
assessment process as needed, and it was not our purpose to discuss the
evolution of our risk assessment process as part of this or any other
plant pest risk assessment. An interpretation of our results and
specific recommendations are provided on p. 48 in the section titled
``Conclusion: Pest Risk Potential and Phytosanitary Measures.'' In that
section we stated that without mitigations, there is a high likelihood
that one or more of the analyzed pests will be introduced. Regarding
the proposed risk mitigation measures, we state that ``an appropriate
level of protection from introduction of plant pests with shipments of
commercial citrus from Argentina requires strict adherence to risk
mitigation measures such as those analyzed in this assessment,'' i.e.,
the proposed risk mitigation measures provide an appropriate level of
protection. With regard to the commenter's statement regarding a
discussion of the ability of additional research or measurement to
improve the risk assessment, it is the very nature of risk assessment
to deal with incomplete information--otherwise, the risk assessment
would be rendered unnecessary. We believe that the available
information is sufficient to support the efficacy of the measures
required by this rule and our analysis of the risks associated with
Argentine citrus.
Economic and Other Analyses
Comment: The proposed rule's economic analysis states that
Argentine citrus would enter the U.S. market at a time when few lemons
are produced by U.S. growers. This is not true. The California lemon
industry has invested heavily in developing specialized lemon trees
that are harvested year round. Moreover, although the peak of the
California harvest comes from March to June, the fruit is capable of
being stored for 90 to 120 days without loss of color, flavor, or
quality. Hence, the great majority of California lemons are sold into
the summer marketplace at the very time Argentina intends to export
fruit.
Response: The proposed rule's economic analysis was not focused on
lemon production alone, as the commenter suggests. Rather, our
consideration of the domestic citrus market was more general.
Specifically, we stated in the proposed rule that ``* * * domestic
shipments of citrus fruit are at their lowest during the months of
July, August, and September, dropping to approximately 3.5 to 5 percent
of average annual shipments * * *. Since the peak production period for
citrus in Argentina is from May to October, the entry of Argentine
fresh citrus fruits would likely peak during these months, which
represent the most likely window of opportunity for Argentine imports
to enter the U.S. market * * *. Importers and brokers would likely
benefit from the entry of Argentine citrus fruit into the U.S. market
because they would be able to provide quality fruits during the months
when domestic production is lowest.'' That discussion in the proposed
rule was intended to illustrate the complementary nature of production
in the northern and southern hemispheres, and not to discount the
potential presence of domestically produced fruit in the marketplace.
Comment: The economic analysis prepared for the proposed rule
provides an inaccurate representation of the potential economic effects
of imported Argentine citrus by: (1) Assuming that oranges, grapefruit
and lemons are in the same product market, i.e., that they are perfect
substitutes in both production and consumption and that a pound of
imported oranges has the same impact on lemon prices as does a pound of
imported lemons; (2) asserting that there is very little U.S. citrus
production during the summer months when most Argentine exports occur
and that few U.S. citrus producers would, therefore, be affected; (3)
assuming that the composition of citrus imports (oranges, grapefruit,
or lemons) does not alter the
[[Page 37658]]
impact of imports; (4) ignoring the multiplier effects of fresh citrus
sales; and (5) assuming that marketing margins are constant and that
price changes at the producer and wholesale levels are transmitted
immediately to the retail level.
Response: The commenter's statements numbered 1, 3, 4, and 5 are
addressed in our final economic analysis set forth in this final rule
under the heading ``Executive Order 12866 and Regulatory Flexibility
Act.'' With regard to point number 2, we noted in the response to the
previous comment that our economic analysis did not discount the
presence of domestically grown fruit in the marketplace during the
summer months. Rather, we stated that because Argentina exports most of
its fresh fruit during the summer months, those imports would not
compete with the peak production season in the United States (late
fall, winter, and early spring), which would limit--not eliminate--the
impact on U.S. producers, exporters, and importers of citrus. In
several places, including both the introduction and conclusion of our
analysis, we explicitly recognized that the magnitude of the economic
effect of Argentine citrus would depend on the additional Argentine
supply, the U.S. supply and demand for citrus, and price conditions in
the rest of the world, and concluded that the larger the share of
Argentine imports, relative to U.S. domestic supply, the larger the
U.S. producer losses and the larger the U.S. consumer gains. We did
not, as the commenter suggests, assert that only a few U.S. producers
would be affected by Argentine citrus imports.
Comment: The economic analysis prepared for the proposed rule fails
to recognize that the growth in Argentine citrus exports has been and
will continue to be concentrated in fresh lemons and that there are
significant amounts of lemons now being processed that could be
diverted to the fresh export market, since the price paid for lemons
for processing is usually much lower than for fresh use. There is,
therefore, the potential that fresh lemon imports from Argentina during
the summer months could likely range from 40 to 100 million pounds, and
not the 10 to 50 million pounds examined in the analysis.
Response: The economic analysis did recognize the growth in
Argentine citrus production and, since that growth is predominantly in
the lemon sector, implicitly recognized the concentration on fresh
lemons noted by the commenter. Indeed, it was the growth in Argentine
citrus production levels that served as the basis for our estimates of
potential imports of Argentine citrus into the United States, as we
expect that Argentina will maintain its well-established export markets
in Europe, given the substantial investment that they have made to
cultivate those markets and the inadvisability of developing a heavy
dependence on a single market such as the United States. With regard to
the diversion of lemons from the processing market to the fresh market,
we acknowledge that fresh lemons bring higher prices than lemons for
processing, but one must also consider that the costs of production
will be higher for those groves producing fresh lemons for the U.S.
export market in light of this rule's requirements for additional
phytosanitary measures during the growing and packing process and the
costs of transporting fresh lemons versus the costs of transporting
concentrated lemon juice and essential oils. With these considerations
in mind, we do not believe that a significant diversion of lemons from
the processing market to the fresh market is likely.
Comment: Section 603 of the Regulatory Flexibility Act requires
agencies to prepare and make available for comment an initial
regulatory flexibility analysis in connection with any proposed rule.
The purpose of the analysis is to assess the impact of the proposed
rule on small entities. While APHIS correctly recognizes that 96
percent of U.S. citrus fruit farms are small entities, it nonetheless
states that ``this action would not have a significant economic impact
on a substantial number of small entities.'' We do not understand how
APHIS could conclude that the approval of citrus imports, some of which
will be in direct competition with domestic growers, would not have a
significant economic impact on a significant number of those small
growers. Thus, APHIS must prepare the analysis required by 5 U.S.C.
603, including the preparation of an analysis of significant
alternatives. Even if APHIS concludes that no significant alternative
exists which can accomplish the stated objectives and minimize the
impact on small growers, this discussion must still be set forth in the
proposed rule.
Response: In the economic analysis provided in the proposed rule,
we identified 17,898 farms producing citrus in the United States and
stated that 96 percent (17,182) of those farms were small entities with
gross sales of less than $500,000. The remaining 4 percent (716) of
those farms had gross sales of more than $500,000 and thus were not
considered small entities under the applicable Small Business
Administration criteria. In the scenario we examined in which 50
million pounds of Argentine citrus entered the United States (the
largest import volume of the five scenarios considered), we stated that
the expected loss to producers would be $36.674 million. When spread
evenly across the 17,898 producers identified, that would amount to a
loss of $2,049 per farm. However, we also noted in our analysis that
the 4 percent of producers who are not small entities owned 66 percent
of the total citrus-growing acreage. If the expected losses are
weighted to the relative shares of citrus-producing acreage, the 17,182
small entities could expect to bear a collective loss of $12,469,160
(i.e., $36.674 million multiplied by 0.34), which amounts to $726 per
small farm. Under section 605(b) of the Regulatory Flexibility Act, the
requirements of section 603 do not apply to any proposed or final rule
if the head of the agency certifies that the rule will not, if
promulgated, have a significant economic impact on a substantial number
of small entities. Thus, our statement in the proposed rule that ``this
action would not have a significant economic impact on a substantial
number of small entities'' was the Administrator's certification of
this minimal effect, as required by section 605(b).
Comment: There is no evidence in the proposed rule that APHIS
prepared an environmental impact assessment of the rule, which should
have been prepared in order for APHIS to comply with the requirements
of the National Environmental Policy Act (NEPA). APHIS' NEPA
implementing regulations in 7 CFR 372.5(b)(1) require the preparation
of such a report. If either the Medfly, various species of Anastrepha,
or possibly other pests were to enter the United States via Argentine
fruit and become established, a significant, and perhaps widespread
spraying program would be required. We submit that APHIS is obligated
to consider this possibility, and prepare, at a minimum, an
environmental impact assessment if such an event were to occur.
Response: For the proposed rule, those issues were considered in
the risk assessment in section 7 (Consequences of Introduction:
Economic/Environmental Importance) of chapter II (Risk Assessment). An
environmental assessment was not prepared for the proposed rule because
APHIS previously decided, in accordance with our NEPA implementing
regulations in 7 CFR 372.5(c), to classify future amendments to 7 CFR
part 319 as categorically excluded actions not requiring the
preparation of an
[[Page 37659]]
environmental assessment. However, in December 1998, following the
publication of the proposed rule, our review and consideration of the
comments that had been received by that time led us to prepare an
environmental assessment that addresses the concerns raised by the
commenter. That environmental assessment, as well as a finding of no
significant impact based on the information presented in the
environmental assessment, may be obtained by contacting the person
listed under FOR FURTHER INFORMATION CONTACT.
Comment: APHIS has failed to prepare a civil rights impact analysis
to analyze the impact of the proposed rule, if adopted, on various
minority groups. The potential for the rule to lead to a significant
loss of jobs for one or more ethnic groups must be considered.
Response: We did in fact prepare a civil rights impact assessment
for the proposed rule. It may be obtained by contacting the person
listed under FOR FURTHER INFORMATION CONTACT.
Miscellaneous
In addition to the changes discussed previously in this document,
we are also amending two other sections of the fruits and vegetables
regulations to correct outdated and erroneous references to several
sections of the regulations, including Sec. 319.56-2f, which will be
the location of this rule's provisions regarding the importation of
grapefruit, lemons, and oranges from Argentina.
Specifically, paragraph (e) of Sec. 319.56a, ``Administrative
instructions and interpretation relating to entry into Guam of fruits
and vegetables under Sec. 319.56,'' refers to ``the provisions of
Secs. 319.56-2d and 319.56-2f to 319.56-2m, inclusive,'' but all of
those sections, with the exception of Sec. 319.56-2d, have been removed
or redesignated since the time the regulations in Sec. 319.56a became
effective in 1959. Therefore, we are amending Sec. 319.56a(e) so that
it accurately reflects the locations of those remaining sections of the
regulations to which it originally referred.
Similarly, we are amending Sec. 319.56-2i to remove a reference to
Sec. 319.56-2f that dates back to when that section contained
provisions regarding the importation of Manila mangoes from Mexico. In
1995, Sec. 319.56-2f was removed and reserved and its provisions
regarding the importation of oranges, grapefruit, and mangoes from
Mexico were integrated into the table contained in Sec. 319.56-2x.
Section 319.56-2i should have been amended at that time to reflect the
removal of Sec. 319.56-2f, but was not. Further, the inclusion of
mangoes from Mexico on the list of commodities in Sec. 319.56-2x that
may be imported subject to treatment in accordance with the PPQ
Treatment Manual means that it is no longer necessary to include
provisions regarding Mexican mangoes in Sec. 319.56-2i. Therefore, we
are amending Sec. 319.56-2i by removing the reference to Mexico from
the title of the section, eliminating paragraph (a)(2), and removing
the reference to Sec. 319.56-2f from paragraph (b).
Therefore, for the reasons set forth in the proposed rule and in
this document, we are adopting the provisions of the proposal as a
final rule with the changes discussed in this document.
Effective Date
This is a substantive rule that relieves restrictions and, pursuant
to the provisions of 5 U.S.C. 553, may be made effective less than 30
days after publication in the Federal Register.
Argentina has demonstrated in accordance with international
standards that the citrus-growing areas of the States of Catamarca,
Jujuy, Salta, and Tucuman are free from citrus canker. Further, we
believe that the phytosanitary requirements contained in this rule to
prevent the introduction of other plant pests will reduce the risks
posed by the importation of grapefruit, lemons, and oranges to a
negligible level. Given these considerations, we believe that it is no
longer necessary to prohibit the importation of grapefruit, lemons, and
oranges from Argentina.
Immediate implementation of this rule is necessary to provide
relief to those persons who are adversely affected by restrictions we
no longer find warranted. This rule requires that certain measures be
taken in order for grapefruit, lemons, and oranges to be imported into
the continental United States, including measures that must be applied
early in the growing season. Making this rule effective immediately
will allow plant health authorities and interested producers in
Argentina to initiate the required measures as the growing season
begins in order for their fruit to be eligible for export to the
continental United States during the 2000 shipping season. Therefore,
the Administrator of the Animal and Plant Health Inspection Service has
determined that this rule should be effective less than 30 days after
publication.
Executive Order 12866 and Regulatory Flexibility Act
This rule has been reviewed under Executive Order 12866. The rule
has been determined to be significant for the purposes of Executive
Order 12866 and, therefore, has been reviewed by the Office of
Management and Budget.
This rule amends the citrus fruit regulations by recognizing a
citrus-growing area within Argentina as being free from citrus canker.
This rule also amends the fruits and vegetables regulations to allow
the importation of grapefruit, lemons, and oranges from the citrus
canker-free area of Argentina under conditions designed to prevent the
introduction into the United States of two other diseases of citrus,
sweet orange scab and citrus black spot, and other plant pests. These
changes will allow grapefruit, lemons, and oranges to be imported into
the continental United States from Argentina subject to certain
conditions.
The entry of Argentine fresh citrus fruits into the continental
United States can be expected to place additional competitive pressure
on domestic producers and on exporters from other countries who
currently market fresh citrus fruits in the United States. The net
benefits of this rule are likely to be positive, where consumers would
benefit from lower prices while producers would likely bear the primary
losses.
Analysis
This analysis, which also serves as our cost-benefit analysis,
considers the potential economic effects on domestic producers and
consumers of citrus of allowing the importation of fresh citrus fruits
from Argentina into the continental United States. Since entry of
Argentine citrus to the continental United States will take place in
three stages, the study focuses on citrus production, price and
potential economic effects of this rule on consumers and producers
during each stage. The major effects considered are losses to domestic
producers and gains to consumers due to decreased prices resulting from
increased volume. The magnitude of the impact will depend on the size
of additional Argentine supply, the U.S. supply and demand for citrus,
and price conditions in the rest of the world. Because Argentina
already has well-established international markets, particularly in
Europe, potential additional Argentine supply to the United States
would likely be limited. After brief overviews of U.S. and Argentine
production and import/export status and a discussion of prices, we
evaluate the impact of increased imports from Argentina on the U.S.
lemon, orange, and grapefruit markets.
The data sources used for the analysis include: USDA, National
Agricultural
[[Page 37660]]
Statistics Service (NASS) production statistics; the 1997 Census of
Agriculture; USDA, Economic Research Service, ``Foreign Agricultural
Trade of the United States''; USDA, Agricultural Marketing Service,
marketing information; USDA, Foreign Agricultural Service, ``Annual
Citrus Report''; and United Nations, Food and Agricultural
Organization, production and trade statistics. A complete bibliography
of the sources used in this analysis is available from the person
listed under FOR FURTHER INFORMATION CONTACT.
U.S. Citrus Industry
Citrus production
The United States produced 30,270 million pounds of grapefruit,
lemons, and oranges (citrus henceforth) in 1996, with a value of $2.4
billion. Four States--Arizona, California, Florida and Texas--accounted
for about 98 percent of the grapefruit, lemon, and orange farms and
more than 99 percent of the acreage in 1997 (the latest census year).
As shown in Table 1, in 1997 there were 4,410 farms in the four
main citrus-producing States that produced grapefruit, 1,978 that
produced lemons, and 13,133 that produced oranges. Approximately 97
percent of these fruit farms (Standard Industrial Classification 0272)
had gross sales of less than $500,000 and thus are considered to be
small entities according to the Small Business Administration size
standards (13 CFR 121.601). These small citrus farms accounted for less
than 34 percent of the total citrus growing acreage, while the
remaining 3 percent of citrus farms (i.e., those with annual gross
sales of $500,000 or more) accounted for about 66 percent of the
acreage.
Table 1.--Farms by State and Type of Citrus, 1997
----------------------------------------------------------------------------------------------------------------
Grapefruit Lemons Oranges
-----------------------------------------------------------------
State Small Small Small
Number of entities Number of entities Number of entities
farms (%) farms (%) farms (%)
----------------------------------------------------------------------------------------------------------------
Arizona....................................... 159 100 154 95 266 98
California.................................... 1,279 97 1,824 93 5,640 98.5
Florida....................................... 2,549 97 ......... ......... 6,893 96.2
Texas......................................... 423 97 ......... ......... 334 99
-----------------------------------------------------------------
Total farms............................... 4,410 ......... 1,978 ......... 13,133 .........
----------------------------------------------------------------------------------------------------------------
Source: USDA/NASS, Census of Agriculture 1997. Note the United States Summary includes farms that may be
producing more than one type of citrus and thus reports fewer farms than when farms are added up by States.
Oranges, grapefruit, and lemons account for about 95 percent of the
total U.S. citrus production. The 1996 value of U.S.-produced oranges
was $1.82 billion; grapefruit, $289 million; and lemons, $261 million.
Table 2 below shows the end use of grapefruit, lemons, and oranges for
the United States (1993/94 to 1997/98 average). As the table shows, the
share of processed fruit is greater than that diverted to the fresh
export market or fresh domestic market.
Table 2.--End Use of Citrus in the United States: Average of 1993/94 to
1997/98
------------------------------------------------------------------------
Percentage to:
--------------------------------------
Fruit Fresh fruit
Export market Processing
------------------------------------------------------------------------
Grapefruit....................... 18.6 28.7 52.7
Lemons........................... 14.4 36.8 48.8
Oranges.......................... 5.4 14.7 79.9
------------------------------------------------------------------------
Source: USDA/ERS, Fruit and Tree Nuts: Situation Outlook Yearbook, FTS-
287, October 1999.
Production for the fresh orange, grapefruit, and lemon markets
accounted for about 25.2 percent of total citrus production or
approximately 8,662 million pounds in 1997/98. The share of citrus
fruits destined for the fresh market varied by State and by fruit.
Table 3 below shows fresh utilized production, fresh fruit share, and
distribution by State.
Table 3.--Fresh Production and Share by State and Type of Citrus, 1993/94 to 1997/98
----------------------------------------------------------------------------------------------------------------
Grapefruit Lemons Oranges
-----------------------------------------------------------------------
State Fresh Fresh Fresh Fresh Fresh Fresh
utilized fruit utilized fruit utilized fruit
production* share (%) production share (%) production share (%)
-----------------------------------------------------------------------*-----------------------*----------------
Arizona................................. 56 68 168 59 84 87
California.............................. 400 68 807 50 3,700 78
Florida................................. 1,904 42 ........... ......... 940 5
Texas................................... 250 70 ........... ......... 69 77
----------------------------------------------------------------------------------------------------------------
* Fresh utilized production is in millions of pounds.
Source: USDA/ERS, Fruit and Tree Nuts: Situation Outlook Yearbook, FTS-287, October 1999.
[[Page 37661]]
As can be seen from Table 3, the fresh market accounted for about
87 percent of the oranges, 68 percent of the grapefruit, and 59 percent
of the lemons produced in Arizona; about 78 percent of the oranges, 68
percent of the grapefruit, and 50 percent of the lemons produced in
California; about 5 percent of the oranges and 42 percent of the
grapefruit produced in Florida; and 77 percent of the oranges and 70
percent of the grapefruit produced in Texas.
The annual average consumption of oranges, grapefruit, and lemons
in the United States has stayed at around 21.7 pounds per person (12.6
pounds of oranges, 6.5 pounds of grapefruit, and 2.4 pounds of lemons),
1977 to 1997, with a variability of about 10 percent. Fresh citrus
fruits are marketed throughout the year, most heavily between October
and May. Table 4 shows the marketing seasons for the fruits, by State.
Table 4.--Marketing Seasons by Fruit and State, 1999
----------------------------------------------------------------------------------------------------------------
Fruit State Marketing season
----------------------------------------------------------------------------------------------------------------
Grapefruit....................... Arizona............. November 1 to July 31.
California.......... November 15 to October 30.
Florida............. September 10 to July 31.
Texas............... October 1 to May 30.
Lemons........................... Arizona............. August 15 to March 1.
California.......... August 1 to July 31.
Oranges.......................... Arizona............. November 1 to August 31.
California (Navels). November 1 to June 15.
California March 15 to December 20.
(Valencias).
Florida (Early and October 1 to April 15.
midseason).
Florida (Valencia).. February 1 to July 31.
Texas............... September 25 to May 15.
----------------------------------------------------------------------------------------------------------------
Source: USDA, NASS, Citrus Fruits 1999 Summary, September 1999.
Domestic shipments of citrus fruit are at their lowest during the
months of July, August, and September (the distribution of oranges
drops to approximately 6.4 percent of average annual shipments,
grapefruit to 0.7 percent, and lemons to 16.3 percent). U.S. citrus
exports are also at their lowest during these months. Citrus imports
are also widely distributed throughout the year, but with above-average
imports during July, August, and September (about 29 percent).
Wholesale prices follow the same seasonal supply patterns, as they are
lower during peak production months--October to May--and higher during
summer months from June to September. Since the peak production period
for citrus in Argentina is from May to October, the entry of Argentine
fresh citrus fruits will likely peak during these months, which
represent the most likely window of opportunity for Argentine imports
to enter the U.S. market. The annual average terminal market wholesale
price in 1996 in major U.S. cities was approximately 40 cents per pound
for oranges, 29 cents per pound for grapefruit, and 43 cents per pound
for lemons. (The average monthly wholesale prices were estimated from
Terminal Market Prices by cities for January to December 1996; USDA/
AMS, Fruit and Vegetable Market News.)
Importers and brokers will likely benefit from the entry of
Argentine citrus fruit into the U.S. market because they will be able
to provide quality fruits during the months when domestic production is
lowest. Consumers will be able to obtain a wide choice of fresh citrus
throughout the year and will not need to wait for the peak domestic
production season or switch to non-citrus fruits.
Citrus Trade
Foreign markets play an increasingly important role for U.S.
producers, accounting for approximately 29 percent of the 1996 annual
fresh citrus fruit sales. The total value of the U.S. fresh grapefruit,
lemon, and orange exports was approximately $659 million in 1996. In
terms of value, oranges accounted for 43.9 percent of citrus exports,
grapefruit for 38.1 percent; and lemons for 18 percent. The United
States is a net exporter of citrus fruits. Imports of fresh grapefruit,
lemons, and oranges were valued at about $26.7 million in 1996; by
value, about 5.4 percent of imports were grapefruit, 10.1 percent were
lemons, and 84.5 percent were oranges.
A few countries accounted for the bulk of the U.S. fresh citrus
export market. In Asia, Japan (46 percent), Hong Kong (10.4 percent),
the Republic of Korea (3 percent), and Taiwan (3 percent) together
accounted for approximately 62.4 percent of total U.S. exports. Next,
exports to Canada were about 25 percent. In Europe, France (3.3
percent), The Netherlands (2.9 percent), and the United Kingdom (1
percent) are the major importers. The United States, as noted above, is
not a major importer of fresh citrus fruits. Major suppliers are
Australia (67 percent), Mexico (13 percent), and Chile (6.2 percent);
these countries together supplied about 86 percent of U.S. fresh citrus
imports in 1996.
U.S. fresh orange exports increased at an average growth rate of
4.2 percent between 1985 and 1996; fresh grapefruit exports increased
by 3.7 percent during that same period. In contrast, exports of lemons
declined by an average rate of 1.1 percent between 1985 and 1996.
Citrus imports to the United States increased at an average annual
growth rate of 10 percent between 1985 and 1996. Imports are heaviest
during the months when U.S. production and shipments are lowest. There
is also a reciprocal window of opportunity for U.S. producers to step
in during the months when production is low in countries of southern
hemisphere. At present, the United States is exporting approximately
$100,000 worth of citrus fruit to Argentina and importing none.
Argentine Citrus Industry
Production
Argentina produced an annual average of 3,104 million pounds of
grapefruit, lemons, and oranges between 1985 and 1996. Of this, about
1,632 million pounds is from three States: Jujuy, Salta, and Tucuman.
(The fourth State affected by this rule--Catamarca--has little to no
commercial citrus production.) Table 5 shows the end use of the three
fruits in Argentina.
[[Page 37662]]
Table 5.--End Use of Citrus in Argentina, 1996-1998 Average
------------------------------------------------------------------------
Percentage to:
-----------------------------------
Fruit Fresh
Export fruit Processing
market
------------------------------------------------------------------------
Grapefruit.......................... 13 69 18
Lemons.............................. 18 15 67
Oranges............................. 11 71 18
------------------------------------------------------------------------
Source: USDA/FAS, Argentina Citrus Annual Report 1999, No. AR9034.
A greater proportion of grapefruit and oranges is consumed
domestically as fresh fruit, while a larger proportion of lemon is
industrially processed.
The annual rate of increase in Argentine citrus production between
1985 and 1996 is attributable mostly to a 4.7 percent increase in lemon
production. For the other citrus varieties, the growth rate was much
less (0.7 percent for oranges and 0.4 percent for grapefruit). Export
growth rates during this period were 15.4 percent for lemons, 4.1
percent for oranges, and 0.7 percent for grapefruit.
Citrus Trade
Argentina is one of South America's major exporters of grapefruit,
lemons, and oranges. It exported 638 million pounds of those varieties
in 1996 and an average of 470 million pounds per year between 1992 and
1996 (433, 334, 445, 500, and 638 million pounds per year,
respectively). Most of that fruit went to Europe, which accounted for
nearly 87 percent of exports. Major destinations included The
Netherlands (52 percent), France (14 percent), Spain (8 percent), the
United Kingdom (10 percent), and Russia (8 percent). Smaller importers
of Argentine citrus include Portugal, Belgium, Germany, Hong Kong, and
Saudi Arabia. Since the majority of the U.S. fresh citrus exports went
to the Far East, the United States and Argentina appear to be serving
distinct markets. Imports of fresh citrus accounted for only about 0.06
percent of the utilized total Argentine citrus supply.
Argentina can be expected to maintain its well-established export
markets, which, as noted in the previous paragraph, are mainly in
Europe. Exports to the United States would provide another potential
outlet for the Argentine citrus industry.
Wholesale Terminal Market Prices
Fresh citrus fruit wholesale prices are lower in Argentina than in
the United States. Average wholesale prices in Argentina for fresh
grapefruit, oranges, and lemons were 17, 18, and 17 cents per pound,
respectively, in 1996. These are lower than the average U.S. wholesale
price of 29, 40, and 43 cents per pound of the respective fresh fruits
for the same period. However, the Argentine wholesale prices do not
reflect the additional costs that exporting these fruits to the United
States would entail; i.e., overland transport cost from northwestern
Argentina to the south-central coast, the sea freight rate, cold
treatment, and the tariff rates, which add about 15 to 20 cents per
pound to the average Argentine wholesale price. In addition, even
before their fruit is exported to the United States, participating
groves will incur added production costs in meeting the requirements of
this rule. These requirements include grove cleaning, grove treatment,
visual survey of groves 20 days prior to harvest, sampling and
laboratory examination of fruit from the grove and buffer area,
registered technicians at each packinghouse to verify the origin of
fruit coming in, and sodium hypochlorite dipping prior to packing.
These additional requirements are expected to add about 3 to 5 cents
per pound to costs. Thus, by the time the fresh citrus from Argentina
arrives at U.S. ports, the gap in prices will be narrower.
Effects on Producers and Consumers
This section of the analysis examines the potential economic
effects on U.S. producers and consumers of allowing fresh lemons,
oranges, and grapefruit from Argentina to enter the U.S. market.
Because of our conclusion that the importation of Argentine citrus
poses a negligible pest risk, we do not believe that it is necessary to
evaluate the costs of pest introduction in this analysis.
This analysis is based on expected additional exports of these
fruits by Argentina.\1\ As noted previously, the entry of Argentine
citrus fruit into the continental United States will be phased in over
three stages. In the first stage (the 2000 and 2001 shipping seasons),
the fruit will be authorized entry into 34 non-citrus-producing, non-
buffer States; in the second stage (the 2002 and 2003 shipping
seasons), the fruit may enter the original 34 States plus an additional
10 buffer States; and in the final stage (beginning with the 2004
shipping season), the fruit may enter all areas of the continental
United States.
A partial equilibrium economic surplus framework is used in this
analysis to consider the benefits and the costs of this rule. Potential
producer losses and gains to consumers are quantified for each citrus
product in terms of changes in producer and consumer surplus resulting
from increased imports from Argentina. This analysis measures the
direct effects of this rule on domestic producers of oranges,
grapefruit, and lemons. Indirect and induced effects on income, output,
and employment are not considered.
To simplify the analysis, supply and demand curves are assumed to
be linear and the supply shift is assumed to be parallel. We use point
estimates for the elasticities of supply and demand, average annual
prices, and estimates of annual U.S. production and annual Argentine
exports in the analysis. We assume U.S. and Argentine citrus are
substitutes for one another. Seasonality in their production,
consumption, and distribution are ignored.
---------------------------------------------------------------------------
\1\ Producers and exporters in Argentina would not have the
flexibility to make adjustments from domestic sales to exports or
from processing to fresh, at least not within a single season. The
rule essentially requires growers to commit their groves to the U.S.
export market before a tree ever blooms, given that they must
register with SENASA prior to the start of the growing season and
begin applying specific phytosanitary measure (e.g., grove cleaning,
field treatments) very early in the season. A non-registered grove
that normally produces fruit for the Argentine domestic fresh or
processing market could not, in response to high U.S. prices, simply
decide to begin shipping fruit to the United States. It is possible
that a profitable shipping season in the U.S. market for Argentine
export could lead additional Argentine growers to enter into the
export program for the following year. Historical export growth is a
good indicator of what could happen. The recent growth in lemon
exports is used to estimate Argintina's fresh lemon exports to the
United States.
---------------------------------------------------------------------------
To estimate the total exports of oranges, lemons, and grapefruit
that could be expected to result from this rule, we use State- and
fruit-specific 1995 production data from three of the four eligible
Argentine States--Jujuy, Salta, and Tucuman. Because export levels for
Argentine citrus fruit have been subject to marked fluctuations over
[[Page 37663]]
time, a simple semi-log model is used to estimate the growth rate of
exports of each of the three fresh fruits. Exports to the United States
are then calculated by assuming that Argentina would maintain its
current exports to the rest of the world and divert its incremental
export to the United States.
Exports from Argentina will depend to a large extent on whether
Argentine citrus will be price competitive with U.S. citrus. Table 6
shows the average annual prices in Argentina, plus shipping and
additional costs imposed by the rule, and U.S. prices. While seasonal
prices can vary substantially from the average, we believe that the
averages provide some sense of the incentives for Argentine citrus
exports to the United States. Price differentials for the three citrus
commodities indicate that Argentine lemons will be able to compete
effectively with U.S. lemons. It is less likely that oranges and
grapefruit from Argentina will have the same competitive advantage and,
therefore, it is less likely that they will be exported to the United
States.
Table 6.--Estimates of Price Differentials for Citrus
----------------------------------------------------------------------------------------------------------------
Per-pound price (dollars)
----------------------------------------------------------------
Price of
Fruit Argentina Transport Additional Argentine Price of
wholesale cost costs due fruit in U.S. fruit
price to rule U.S.
----------------------------------------------------------------------------------------------------------------
Grapefruit..................................... .17 .15-.20 .03-.05 .35-.42 .29
Oranges........................................ .18 .15-.20 .03-.05 .36-.43 .40
Lemons......................................... .17 .15-.20 .03-.05 .35-.42 .43
----------------------------------------------------------------------------------------------------------------
Lemons
Using a 5-year average (1992/93 through 1996/97) of U.S.
consumption, production plus imports minus exports, we estimated U.S.
domestic consumption of lemons to be 728 million pounds. The average
price is $0.43 per pound. There are very few published elasticity
estimates available. Published estimates from quantity-dependent models
for lemon demand elasticity are not available, but Ferguson and Carman
find an elasticity of demand for lemon of -0.44 in an unpublished
study. Another study yielded an elasticity of supply for lemons greater
than zero (Kinney et al., 1987, p.9, equation 6). Estimation by various
data points, using acreage and per-acre revenue data in Tables 9 and 6,
respectively, of Kinney et al. yields elasticities of supply for lemons
between 0.04 and 0.17. In our analysis we use the -0.44 estimate for
the elasticity of demand and assume an elasticity of supply equal to
0.09.
Because export levels for Argentine lemons have been subject to
marked fluctuations over time (e.g., increases of 73 percent in 1994,
17 percent in 1995, 49 percent in 1996, and almost 10 percent in 1997
and decreases of 55 percent in 1986, 15 percent in 1989, and 25 percent
in 1993), the quantities of fruit considered in this analysis are based
on growth rates in Argentina's fresh lemon exports to the rest of the
world. As discussed above, a simple semi-log model was used to estimate
the growth rate of lemon exports between 1985 and 1998. The results
show that lemon exports increased at the rate of 15 percent during that
period. Using 1994-1998 average exports from the eligible Argentine
States, 293.6 million pounds, as a baseline number, the total expected
increase in exports would be 44.04 (293.6 x 0.15) or, rounding, 44
million pounds.
We assume that the elasticities, the quantity of the domestic
lemons produced and consumed, and the quantity of Argentine lemons
imported would not change over the 3-stage phase-in period.
Estimated results of introducing imported fresh lemons from the
Argentine States of Jujuy, Salta, and Tucuman into the U.S. market are
as shown in Tables 7, 8, and 9. Because the price differential between
Argentine lemons and U.S.-produced lemons shown in Table 6 appears to
be sufficient to make export of lemons profitable to Argentine
exporters, we estimate the impacts on consumers and producers
considering three scenarios for each phase of the rule's
implementation. The three scenarios examine the impact of 60 percent,
80 percent, and 100 percent of the 44-million-pound increase in lemon
exports being shipped to U.S. markets.
We assume that the elasticities and the quantity of Argentine
lemons imported would not change over the 3-stage phase-in. Our point
of comparison in each stage is the absence of lemon imports from
Argentina. In other words, the analysis at each stage assumes the same
level of domestic production and consumption and the same price prior
to importation of Argentine lemons. We have made no attempt to assess
the incremental effects of the rule over the 3-stage phase-in period
and, furthermore, it is not appropriate to compare the impacts of the
various stages or to sum across the stages to obtain a total effect.
Table 7 provides an analysis of expected impacts during Stage 1,
including percent change in price, percent change in quantity,
resultant producer losses, consumer benefits, and net benefits, for
each diversion scenario. Stage 1 allows for importation of citrus into
34 States. These States account for approximately 60 percent of fresh
lemon consumption in the United States, about 437 million pounds.
Table 7.--The Importation of Fresh Lemons From Argentina to Approved
States (Stage 1)
------------------------------------------------------------------------
Percentage of average Argentine lemon
export growth diverted to the U.S.
market:
--------------------------------------
60 80 100
------------------------------------------------------------------------
Imports (millions of pounds)..... 26.4 35.2 44
Percent change in price.......... -11.4 -15.2 -19
Percent change in quantity....... -1.03 -1.37 -1.71
[[Page 37664]]
Decrease in producer surplus -22.251 -29.616 -36.957
(millions of dollars)...........
Increase in consumer surplus 22.926 30.817 38.833
(millions of dollars)...........
Net benefit (millions of dollars) 0.675 1.201 1.876
------------------------------------------------------------------------
As Table 7 shows, during the first stage producer losses could
potentially range between $22.251 million and about $36.957 million,
while consumer gains could range between $22.926 million and $38.33
million. The net benefits, therefore, would be between $675,000 and
about $1.876 million.
In Stage 2, Argentine imports will be shipped to 44 States, which
account for 72.4 percent of lemon consumption, approximately 527
million pounds. Table 8 shows that the expansion in Stage 2 will yield
about the same results as Stage 1.
Table 8.--The Importation of Fresh Lemons From Argentina to Approved
States (Stage 2)
------------------------------------------------------------------------
Percentage of average Argentine lemon
export growth diverted to the U.S.
market:
--------------------------------------
60 80 100
------------------------------------------------------------------------
Imports (millions of pounds)..... 26.4 35.2 44
Percent change in price.......... -9.452 -12.602 -15.753
Percent change in quantity....... -0.851 -1.134 -1.418
Decrease in producer surplus -22.270 -29.651 -37.011
(millions of dollars)...........
Increase in consumer surplus 22.830 30.647 38.567
(millions of dollars)...........
Net benefit (millions of dollars) 0.560 0.996 1.556
------------------------------------------------------------------------
Table 9 presents the results for the third stage, when fresh lemons
imported from Argentina are allowed in all areas of the continental
United States.
Table 9.--The Importation of Fresh Lemons From Argentina (Stage 3)
------------------------------------------------------------------------
Percentage of average Argentine lemon
export growth diverted to the U.S.
market:
--------------------------------------
60 80 100
------------------------------------------------------------------------
Imports (millions of pounds)..... 26.4 35.2 44
Percent change in price.......... -6.84 -9.12 -11.4
Percent change in quantity....... -0.62 -0.82 -1.03
Decrease in producer surplus -21.35 -28.44 -35.52
(millions of dollars)...........
Increase in consumer surplus 21.74 29.13 36.59
(millions of dollars)...........
Net benefit (millions of dollars) 0.39 0.69 1.07
robop...@us.govnews.org
Posting-number: Volume 65, Issue 116, Page 37607, Part 1
[[Page 37648]]
in a grove or buffer area as a result of the sampling will result in
the elimination of the grove and the fruit it produces from the export
program. Thus, the nature of the sampling protocol used for the export
program does not affect the structure of the model because the sampling
is outside the scope of the model; the risk model deals only with fruit
from groves that have been cleared for participation in the program.
In response to the comments regarding this sampling protocol, we
are modifying the protocol for the 20-day preharvest sample and
clarifying the basis and details of the sampling. The sampling protocol
will be based on a statistically valid hypergeometric distribution. The
``lot size,'' or population size, is equal to the number of trees in
the grove and buffer area. We will set our desired level of detection
as follows: We will sample enough trees to have a confidence level of
at least 95 percent of detecting an infection rate of 1 percent or more
of the trees. In preparing this protocol, we have assumed that there
will be 250 trees per hectare, and we have assumed a maximum grove/
buffer area size of 800 hectares based on our available information.
Given those two assumptions, we will require that 298 trees be sampled
from each grove and buffer area (if an area to be sampled exceeds 800
hectares, this rule provides that SENASA will contact APHIS, and APHIS
will determine the number of trees to be sampled). The 298 trees must
be selected at random. In order to increase the likelihood of detecting
disease, the fruit must be sampled from portions of the trees that are
mostly likely to have infected, symptomatic fruit (i.e. near the outer,
upper part of the canopy on the sides of the tree that receive the most
sunlight). We have set the number of fruit to be sampled from each tree
(number of replicates) at four fruit per tree.
Sampling 4 fruit from each of 298 trees will yield a sample size of
1,192 fruit, which is somewhat less than what would result from
sampling 800 hectares at the rate called for in the proposed rule (320
fruit from each 200 hectares, i.e., 1,280 fruit). However, given that
this new sampling protocol is based on a statistically valid
hypergeometric distribution, we believe that it provides the
``statistically adequate'' sampling regime called for by the commenter
and, given its random selection of trees and focus on collecting fruit
from those parts of the tree most likely to contain infected fruit,
will, as suggested by the commenter, ``account for nonuniform infection
rates between groves, and even infection rates that vary within each
grove.''
This sampling protocol will provide information regarding the
disease status of farms wishing to be included in the program to export
citrus fruit to the United States. Our risk model focuses on the risk
to the United States of imported citrus fruit from farms in Argentina
that are part of the official export program, i.e., farms that have
already been certified for export to the United States. There are
numerous risk mitigation measures in place, both as part of the regular
risk mitigation program and the various special requirements of the
U.S. export program. We believe that the testing and inspections
required by this rule will ensure that fruit with a startlingly high
infection rate does not enter the United States.
Comment: The sampling of 320 fruit per 200 hectares shortly before
harvest is an utterly insufficient sample size to be assured of
detecting the presence of citrus black spot or sweet orange scab:
<bullet> At an 8 m x 5 m planting density, there would be 50,000
trees/200 hectares; if 320 fruit are sampled, then 0.64 percent of all
the trees would be sampled. If one assumes only 250 fruit are harvested
per tree, then 0.00256 percent of the harvested fruit is sampled.
<bullet> At a 10 m x 5 m planting density, there would be 40,000
trees/200 hectares; if 320 fruit are sampled, then 0.8 percent of all
the trees would be sampled. If one assumes only 250 fruit are harvested
per tree, then 0.0032 percent of the harvested fruit is sampled.
This sampling size is especially inadequate when one considers that
disease incidence will be low due to the fungicide treatments. Further,
the ability of a sampling program to detect, for example, citrus black
spot, may depend upon the location of the trees sampled within the
grove, the location of the samples on those trees, the age of the
trees, etc. Sample size should be based on biometric principles that
consider the characteristics of the disease, the incidence, and the
level of precision desired to detect any present infections. APHIS
should explain why the 320 fruit/200 hectares sample size was chosen
and why it is appropriate for the desired purpose.
Response: As explained in the response to the previous comment, the
sampling protocol has been modified in this final rule to provide a
statistically valid hypergeometric distribution that will provide for
the sampling of enough trees to have a 95 percent confidence level of
detecting an infection rate of 1 percent or more of the trees, and we
have provided for four replicates per tree. The sampling system
described in the proposed rule was the protocol offered by Argentina
and was designed to be consistent with Argentina's existing monitoring
system for citrus canker, which was based on a transect design.
Comment: The probabilistic estimation for ``pathogen not detected
at packinghouse inspection'' relies here on the results of the 20-day
preharvest sampling results. But, this sampling consists of random
collection of fruit at a rate of 320 fruit from each 200 hectares
surveyed. No information on the statistical or biometrical validity of
this sampling protocol is provided in the pest risk assessment or the
proposed rule. Without this information, it is impossible to evaluate
its impact as a safeguarding element, particularly as it relates to the
mitigation scenario estimation.
Response: As discussed in the responses to the previous comments,
we have modified the sampling protocol that will be used to collect the
fruit that will be subjected to laboratory analysis. Also, the
commenter inaccurately states that ``the probabilistic estimation for
`pathogen not detected at packinghouse inspection' relies here on the
results of the 20-day preharvest sampling results.'' We understand,
however, how the reader could reach that conclusion based on our
statements on p. 38 in section 8.f P3 of the risk assessment, which may
have given a false impression. To clarify, the packinghouse inspection,
and our estimates regarding the likelihood of detecting pests during
this inspection, are independent of both the 20-day preharvest sampling
protocol and the results of that sampling. If any disease is detected
as a result of the 20-day preharvest sampling, none of the fruit from
that grove can be shipped to the United States. The only fruit that
will be inspected and subsequently shipped to the United States are
fruit from groves where the 20-day preharvest sampling resulted in a
finding of no disease. The 20-day preharvest sampling, which would be
conducted to detect the presence of citrus black spot in the grove and
buffer area, was accounted for in the risk model in P1, the likelihood
that harvested fruit is infected. Upon reconsideration, our estimates
for this node should probably be considerably lower, given the rigor of
the 20-day preharvest sample. This sample must be taken from all groves
that ship fruit to the United States.
[[Page 37649]]
Comment: Because we recognize that it is not practical to hold all
harvested fruit for up to 3 weeks to detect latent symptoms, we suggest
that the number of fruit examined in the 20-day preharvest sample be
increased by at least tenfold to reduce the risk of disease
introduction.
Response: Because the sampling protocol required by this rule will
provide for the sampling of enough trees to have a 95 percent
confidence level of detecting an infection rate of 1 percent or more of
the trees, and because the sampling protocol requires four fruit to be
selected from each tree, with those fruit being chosen from the portion
of the tree most likely to have infected fruit, there is almost no
chance that infection could exist in a grove without infected fruit
being included in the sample subjected to laboratory examination.
Further, during the 20 days that the sampled fruit is in the
laboratory, the fruit will be held under conditions that are ideal for
the expression of symptoms in any infected fruit. Given those
considerations, and given that the detection of symptoms in a single
fruit will result in a grove being removed from the export program, we
do not believe that a tenfold increase in the sample size is necessary.
Comment: It is possible to design testing requirements that will
reduce the failure rate below any given value under normal
circumstances, but the risk assessment ought also to evaluate the
effect of abnormal or unusual events. For example, the following need
to be explicitly evaluated:
<bullet> Failure to apply field control (copper oxychloride)
treatment (e.g. through inadvertent failure to add the solution, etc.);
<bullet> Failure of the field control treatment, even if applied;
<bullet> Failure to include the chlorine dip in the treatment
schedule;
<bullet> Failure of the chlorine dip itself (e.g. inadvertent
neutralization or failure to refresh or test);
<bullet> Temporary or permanent failure of inspection machinery
(e.g. through operator inattention);
<bullet> Reintroduction of culled fruit (from harvest culling, if
any, and/or packing plant inspection) into the product;
<bullet> Infection through the use of the same packinghouse at
different times for U.S. export and non-U.S. export fruit (e.g. by
accidental inclusion of non-export fruit still in the packinghouse; or
by infection carried on machinery); and
<bullet> Infection through failure to disinfect tools, clothing
etc. used in U.S. export groves after being used elsewhere.
Response: Our entire model is a fault model; thus, it takes into
account the kinds of events suggested by the commenter, e.g.:
<bullet> Failures in the application or efficacy of field
treatments are considered in the probabilities constructed for node P1,
``Harvested fruit is infected'';
<bullet> Failures in the application or efficacy of the chlorine
dips are considered in the probabilities constructed for node P4,
``Fungus survives post-harvest treatment'';
<bullet> Inspection failures are considered in the probabilities
constructed for P2, ``Pathogen not detected during harvest,'' and node
P3, ``Pathogen not detected at packing house inspection.''
As discussed in our responses to earlier comments, measures will be
in place to prevent non-export fruit from being present in the
packinghouses when any export fruit is present and we believe that it
is unlikely that fruit could become infected as a result of coming in
contact with packinghouse machinery or tools, clothing, etc. Finally,
the risk mitigation program has a series of checks to confirm that the
required steps have been taken.
Comment: From the time the fruit leaves the packinghouse to the
time it arrives at the U.S. port of entry, the only control system
applied is the labeling on the boxes. APHIS has not evaluated the
possibility for deliberate introduction of export-labeled boxes of
untreated fruit in transit, for which there is presumably considerable
economic incentive, nor for the possibility of misdirected, non-export-
labeled boxes containing infected fruit that are missed by U.S. port-
of-entry inspection.
Response: The commenter states that there is ``presumably
considerable economic incentive'' for the deliberate placement of
nonprogram fruit in export-labeled boxes. We disagree, and would argue
that there are actually economic disincentives for such actions. As
stated in the proposed rule and in this final rule, the detection of
citrus black spot or sweet orange scab during the course of any
inspection or testing required by this rule will result in the grove in
which the fruit was grown or is being grown being removed from the
SENASA citrus export program for the remainder of that year's growing
and harvest season, and the fruit harvested from that grove may not be
imported into the United States from the time of detection through the
remainder of that shipping season. Because citrus fruit from
nonparticipating groves is more likely to be infected with citrus black
spot or sweet orange scab than fruit grown in registered groves, we
believe that it is unlikely that the growers and packers participating
in the SENASA citrus export program (and incurring additional costs of
production by doing so) would allow their entire export operation to be
jeopardized by allowing potentially infected fruit from
nonparticipating groves to be commingled with their export-quality
fruit, especially given that Argentina already has strong domestic
demand for its citrus and numerous well-developed export markets to
which nonprogram fruit may be exported. In addition to that purely
economic disincentive, SENASA inspectors will also be present in the
groves and packinghouses during the growing, harvest, and shipping
seasons to ensure that all requirements of the regulations are being
observed.
Regarding the possibility of misdirected, non-export-labeled boxes
containing infected fruit being missed by U.S. port-of-entry
inspection, we believe that it is unlikely that such misdirection would
occur, given that this rule prohibits non-export fruit from being in
the packinghouse when export fruit is present. That being said, the
possibility of boxes containing infected fruit arriving in the United
States is considered throughout the model. The model is a fault model
and estimates the probability of pests entering the United States and
becoming established. Each of these nodes are assumed to be independent
events and, as such, begin with the assumption that pests, in some
form, have infested or infected the fruit (P1), avoided detection (P2,
P3), survived treatment (P4), survived shipment (P5), been shipped to a
suitable habitat (P6), found a suitable host (P7), and will be able to
complete the disease cycle (P8). As such, each of these nodes
represents a ``fault'' in the system. One such fault that could lead to
infected or infested fruit being inserted into the system includes
boxes of fruit that are not part of the system being inserted into the
system.
Comment: Because the proposed rule does not include any
safeguarding requirements on the fruit as it is moved from the grove to
the packinghouse and from the packinghouse to the point of export, the
risk assessment needs to include an evaluation of the probabilities for
infection with citrus diseases or contamination with infected material
(e.g. blown leaves, ascospores attaching to fruit or fruit boxes)
during transport within Argentina. Examination of the transport system
must include staging areas on the road and in port, and must take
account of simultaneous movement of other fruit that has not been
subject to the same
[[Page 37650]]
sanitary requirements as the U.S. export fruit.
Response: Mature fruit is not susceptible to infection by citrus
black spot or sweet orange scab, so the possibility of infection during
transport is not relevant and, therefore, did not need to be considered
in the pest risk assessment.
Comment: APHIS estimates the fraction of the United States that is
suitable habitat for fruit flies to be 10 to 15 percent, and the
fraction of the United States that is suitable for sweet orange scab,
citrus black spot, and citrus canker to be approximately 9 percent.
From the text of the risk assessment, it appears that these values are
simply a fraction of the area of the United States. A more appropriate
value would be the probability that fruit will actually be shipped to
an area with a suitable habitat. Such a distribution should take
account of the population of the United States that lives in suitable
habitats or current (or potential) shipping patterns for fresh citrus.
The distribution should take account of the seasonal probability of
shipping fruit to a citrus-growing region, and the correlation of this
probability with the probability for pest survival.
Response: We have no reason to believe that the analysis suggested
by the commenter would result in a different distribution than the ones
we used. As we noted in response to an earlier comment, with the large
citrus markets throughout the United States, we have no reason to
believe that our estimate of 5 percent (percentage of imported fruit
that will be shipped to areas where citrus can survive) is too low or
too high. Nor have we received any specific information from any
commenter that would allow us to change our estimate. Further, we do
not believe that human population density or shipping patterns for
citrus fruit are relevant when one is considering whether or not an
area provides a suitable habitat for an organism, as that suitability
is more a function of climate and the availability of host material.
The ability of an area to support a pest population exists regardless
of the factors raised by the commenter.
Comment: The U.S. segment of the pathway is identical in the risk
assessment for the baseline and the mitigation program. The probability
distributions appear to be pure guesswork by APHIS (so far as can be
evaluated from the documentation in the risk assessment and proposed
rule). There is no indication of the potential infection routes that
were considered, nor of the use of any data either on prior infections
elsewhere in the world or (except to a minor extent for fruit flies) on
the population biology of the pests themselves.
Response: There is no evidence, nor any reason to believe, that
these diseases have ever been introduced by this pathway--i.e.,
commercial shipment of citrus fruit--or a similar pathway anywhere in
the world. Every scientific reference--and the known biology of these
diseases--indicates that other pathways are responsible for
introductions that have occurred. Because our risk assessment focused
on the commercial shipment pathway, it did not consider other pathways
such as the smuggling of plant material and nursery stock, which is by
far considered the most likely pathway for introduction in all known
introductions with uncertain cause. Our estimates resulted from our
consideration of a variety of potential infection routes, such as
consumers discarding rinds or whole fruit in compost heaps in the
vicinity of citrus trees on their property, and rinds or fruit
discarded in orchards. The scope of our risk assessment and
consideration of potential infection routes are discussed in greater
detail in our response to the next comment.
Comment: There are multiple potential pathways for pests to get
into U.S. citrus areas or other areas of concern. Without
documentation, it is impossible to evaluate whether APHIS has
considered all of them in the risk assessment, and it is impossible to
evaluate their relative importance. For example, citrus groves or
backyard trees could be exposed to pests by a fruit or peel discarded
by workers, trespassers, or passers-by; by peels placed in compost
piles; by truck accidents scattering fruit; and by air dispersion of
spores or contaminated material from ventilated trucks. Indeed, the
probability of discarded fruit will be higher for sweet orange scab or
citrus black spot infected fruit, since a consumer is more likely to
discard fruit in which infection has become apparent. All these
examples could readily be examined using event-tree modeling, using
available data on consumption of raw fruit, human activity patterns,
accident statistics, shipping statistics, and so forth. It should also
be noted that most of the pathways by which infections might take hold
in the United States are based on single fruit, not on boxes. Thus any
quantitative risk assessment for these pathways would most readily (and
possibly can only) be conducted on a ``per fruit'' basis, not on a
``per box'' basis.
Response: The purpose of the risk assessment, as stated in the
first sentence of the risk assessment on p. 1, is ``* * * to examine
plant pest risks associated with the importation into the United States
of fresh citrus fruit grown in certain areas of Argentina.'' The
document is a commodity-based risk assessment conducted to inform the
decision of whether commercial citrus from Argentina should be
enterable under a specific set of mitigation measures. It was not the
purpose of the risk assessment to consider all the various pathways by
which citrus pests could enter the United States. A plant pest risk
assessment that considers all the different pathways by which a pest
can enter an area, which is referred to as a pest-initiated risk
assessment, would be the appropriate vehicle for conducting the types
of analyses suggested by the commenter.
That being said, the possibility that citrus groves or backyard
trees could be exposed to the pathogen via discarded fruit or peel was
considered in our risk assessment (P7, Pathogen reaches suitable host).
We concluded that it is highly unlikely that infected fruit producing
viable pycnidiospores will ever reach the United States. If this did
occur and the fruit or peel was thrown in a compost heap, even under a
backyard citrus tree, it would be highly unlikely that fruit in the
tree could become infected. The pycnidiospores are only waterborne and,
therefore, can only infect fruit when the inoculum source is in direct
contact with or physically close to fruit on the tree, or if there was
fruit positioned beneath the inoculum source so that the spores could
drip onto that lower-hanging fruit. This also would assume that the
environmental conditions were favorable for infection and that fruit
were susceptible. Realistically, it would be difficult to infect U.S.
fruit, even if infected fruit was purposely placed in the tree canopy.
In greenhouse inoculation studies conducted by an APHIS scientist, it
was necessary to place fungal cultures of citrus black spot directly on
susceptible fruit and to keep the inoculum and fruit moist for nearly 7
days. Even under these highly favorable conditions, not all inoculated
fruit became infected. Thus, the likelihood of infection in the field,
even by symptomatic fruit, is very low. Finally, we believe that our
use of the box as the risk unit, as opposed to the individual fruit as
the commenter suggests, is an appropriate choice. Retail boxes stay
intact from the packinghouse until their point of final sale (e.g., a
supermarket), and it is reasonable to assume that most or all of the
fruit in a box would be used, and the remains
[[Page 37651]]
discarded, in the same general vicinity (e.g., town, neighborhood) as
the point of final sale.
Comment: For the U.S. segment of the pathway considered (including
shipping), APHIS estimates the probability for citrus black spot
outbreak to be about 10<SUP>-9</SUP> per infected 18-kg box (0.83 0.05
x 0.005 x 0.000005), using the mean values for the distributions
given in Table 9 of the risk assessment. The total U.S. consumption of
fresh citrus fruit is about 25 lbs/person/yr, or 2.8 x 10<SUP>9</SUP>
kg/yr, or 1.6 x 10<SUP>8</SUP> boxes/yr at 18 kg/box. Thus, APHIS is
effectively suggesting that if the entire U.S. fresh citrus fruit
supply were imported, and it was all infected at source (100 percent),
the probability for a citrus black spot outbreak in the United States
would be on the order of 0.16 per year. This is an unreasonable
prediction, given the experiences elsewhere with citrus black spot
infection. Note that the APHIS approach (on a ``per box'' basis) cannot
apparently distinguish between 1 infected fruit per box, and 100
percent infected fruit in a box, whereas these clearly pose different
risks.
Response: First, as explained in the response to the previous
comment and elsewhere in this document, we believe that a box of fruit
is an appropriate risk unit. Second, given the preponderance of
evidence and expert opinion that long distance spread of Guignardia
citricarpa via infected fruit is unlikely, and the dearth of documented
cases of such spread, we believe that the probability calculated by the
commenter is not unreasonable and our distributions, therefore, are
appropriate. We offer the following citations from the scientific
literature to support our conclusions:
<bullet> ``Ascocarps of the pathogen have never been found on fruit
and the pycnidiospores are not airborne. Therefore, disease spread is
unlikely through the movement of infected fruit.'' (Whiteside, J.O.;
Garnsey, S.M.; Timmer, L.W. 1988. St. Paul, MN: American
Phytopathological Society. 80 p.).
<bullet> ``The fungus can readily be carried on imported citrus
fruits, but the risk of spread from these is relatively low.'' (Smith,
I.M.; McNamara, D.G.; Scott, P.R.; Holderness, M.; Burger, B. 1997.
Quarantine Pests for Europe. New York: CAB International. 1,425 p.).
<bullet> ``Fruit cannot rate high as an effective source of
inoculum (pathway) in international trade. Ascospores have never been
found on fruit, but pycnidiospores are produced that are not
airborne.'' (Santacroce, N.G. 1982. ``Guignardia citricarpa Kiely.''
Hyattsville, MD: USDA, APHIS, BASS. 7 p.)
Comment: To provide a reliable risk assessment, APHIS must provide
documentation according to the procedure of Kaplan (1992), which APHIS
claims to have followed in preparing the risk assessment. First, this
documentation must explicitly lay out the evidence upon which the
probability distributions are based, including any disagreements
between the experts. Second, it must show the reasoning leading from
the evidence to the distributions. Third, APHIS should state the names
of the experts involved, and the risk assessors involved. In several
places throughout the risk assessment, there is confusion between the
experts and the authors--or are they the same, and does this violate
the spirit of Kaplan's approach? We suggest that if the experts and the
risk assessors are the same people, then the spirit of Kaplan's
approach requires a substantially larger effort to separately document
the evidence and the line of reasoning taken in obtaining distributions
from such evidence.
Response: The reliability of a risk assessment depends on the
extent to which it accurately represents the actual risk. We agree,
however, that it is important to document the basis of a risk
assessment so that readers can make judgments about the validity of the
information in the risk assessment. That is why we provided extensive
information and references concerning the scientific information that
formed the basis of our risk assessment. The information, scientific
data, and evidence used to estimate the appropriate input values
(distributions) was cited in the 162 scientific references, 13
regulatory references, and supporting documents cited in the risk
assessment. Specifics about how this information was interpreted and
used is provided in the discussions for each of the nodes in our model
(sections 8.e. and 8.f.) and in the pest data sheets prepared for, and
presented in, the risk assessment (Appendices I through VII). The three
authors of the document are listed on the cover sheet. Tables 7 through
10 list the 72 node estimates used to conduct the Monte Carlo portion
of the risk assessment. Each estimate consists of a distribution type
and estimates for the distribution parameters. The exact list of
experts used to estimate each of the 72 distributions varied from node
to node. However, section IV of the risk assessment (``Preparation,
Consultation and Review,'' pp. 58-59) lists the 21 experts (including
the three authors) within and outside USDA who were consulted during
production of the risk assessment. While the three authors did, in some
cases, double as both risk assessors and experts, we believe that the
review provided by the remaining 18 listed experts who were consulted,
as well as the State regulatory personnel and others who reviewed the
risk assessment in its draft form, preclude the lending of any undue
weight to the opinions of the authors when it was necessary for them to
act in both capacities.
Comment: The FAO ``Guidelines for Pest Risk Analysis'' provide that
risk assessments must be well documented: ``A risk assessment [pest
risk analysis] should be sufficiently documented so that when a review
or a dispute arises, the risk assessment will clearly state the sources
of information and the rationales used in reaching a management
decision regarding phytosanitary measures taken or to be taken'' (FAO,
International Standards for Phytosanitary Measures, adopted November
1995 by the 28th Session of the FAO Conference, p. 20). In contrast to
the FAO requirements, however, the 1997 risk assessment does not
disclose the sources of much of the data relied upon, the basis for a
number of assumptions relied upon, nor the names of particular experts
who were looked to for estimates that are used in the risk assessment.
Response: The commenter states that we did not disclose the sources
of much of the data relied upon, but we believe that we thoroughly
documented our sources of information in section III of the risk
assessment (References) and in the references listed at the end of each
of the pest data sheets provided as appendices.
The commenter states that we did not disclose the basis for a
number of assumptions relied upon, but we did provide a narrative
discussion of how we arrived at probabilities used in each of the nodes
for each of the pests of concern (fruit flies and diseases). While the
information we provided for each node may not have contained the level
of detail that the commenter appears to believe would have been
appropriate, we did attempt to describe how we arrived at each of our
estimates in those discussions rather than simply reporting our
estimates in table form. Additional information regarding the
construction of our distributions is provided in the addendum to the
risk assessment that may be obtained from the person listed under FOR
FURTHER INFORMATION CONTACT.
The commenter states that we did not disclose the names of
particular experts who were looked to for estimates that
[[Page 37652]]
are used in the risk assessment, but section IV of the risk assessment
(Preparation, Consultation, and Review) lists the names of each of the
entomologists, botanists, plant pathologists, agriculturalists, plant
virologists, and information specialists who participated in the
preparation of the assessment, as well as the names of the APHIS and
State personnel who were consulted during the preparation of the
assessment and who reviewed drafts of the assessment. As can be seen by
the Argentine citrus risk assessment and our previous risk assessments,
it has not been our normal practice to explicitly tie individual
experts to the estimates provided for specific nodes; we will, however,
consider doing so in future risk assessments.
Comment: Variability represents known heterogeneity of a quantity.
Uncertainty represents lack of knowledge about that quantity that could
be better characterized with further research and/or measurement.
Variability and uncertainty should be considered separately in a Monte
Carlo risk assessment, so that one can identify the sources of the
spread in the resulting distribution. A final risk distribution might
be interpreted very differently if the source of most of the spread
were uncertainty than if the source were true variability in the input
parameters. The APHIS risk assessment focuses primarily on uncertainty,
with a smaller emphasis on variability, but APHIS makes no distinction
between the two in its risk assessment calculations. Moreover, APHIS
seems to confuse the two when it states, ``Uncertainty in the estimated
values may arise from natural variation over time, natural variation
from place to place, data gaps or unconfirmed data, [and] relationships
among multiple components in a node.'' Many of the distributions
presented in the risk assessment are claimed to be uncertainty
distributions for probabilities, but since the methods used to elicit
these distributions are not specified, we cannot evaluate whether the
distinctions between variability and uncertainty were maintained during
the elicitation. The object of the risk assessment is not adequately
specified with respect to variability and uncertainty, but the most
logical interpretation would exclude year-to-year variability as being
of great interest. However, such year-to-year variability is explicitly
included in at least one distribution incorporated in the assessment.
Response: As noted in a recent paper published in the journal Risk
Analysis (Gray et al., 1998) and cited in response to a previous
comment, [k]nowledge of variability must be based on empirical
estimates, otherwise it is another source of uncertainty. With the
exception of one or two nodes, data providing an estimate of
``variability (as it) represents known heterogeneity of a quantity'' do
not exist for these parameters. Accounting separately for variability
and other forms of uncertainty in this risk assessment would constitute
overinterpretation of available data. Overinterpretation of available
data would most likely lead to risk estimates that are less, rather
than more, accurate.
Comment: APHIS states that the risk analysis computer software
package @Risk for Excel (Palisade Corp., Newfield, NY) is used to run
the Monte Carlo Analysis. However, APHIS does not state which version
of this software was used, in what spreadsheet package, nor where to
find technical details of the software that are necessary to critically
evaluate the adequacy of this software for the assessment. The
spreadsheet itself is not included in the risk assessment or in the
rulemaking record. To ensure reproducibility of the analysis, APHIS
should at least document which version of @Risk was used, and should
provide a copy of the spreadsheet used for the analysis. We have
reservations that even this is sufficient, since required technical
details of @Risk are not publicly available. These include such
important details as the algorithm used to generate (pseudo) random
numbers. Other software packages with similar capabilities make
technical details available.
Response: We used @Risk for Excel, version 3.5c, to run the
analysis. We did not supply the ``required technical details of @Risk''
because we believed that sufficient information--i.e., all the
technical information the software company has chosen to make publicly
available was provided in the @Risk documentation. We concluded that
including the spreadsheets would provide no new information; the risk
model (i.e., the calculations used) is completely described and
adequately represented in Figure 2 (p. 30) and section 8.b. (p. 28) of
the risk assessment, and all input values used in all spreadsheets are
completely specified in Tables 7 through 10. The spreadsheets
themselves may be obtained from the person listed under FOR FURTHER
INFORMATION CONTACT.
Comment: Although the primary focus of the risk assessment is, as
it should be, on pests that affect or are present on Argentine citrus
crops, the citrus fruit itself is not the only item that will be
imported. The fruit will be packed in crates or boxes and shipped on
pallets. The North American Plant Protection Organization (NAPPO) has
recognized that a large percentage of wood dunnage or packing materials
moving in international trade is composed of low quality, inexpensive
wood products that may contain quarantine pests. The structure of the
model used by APHIS does not allow problems such as this to be
addressed in the risk assessment.
Response: APHIS recognizes the plant pest risk presented by solid
wood packing materials and has separate regulations in 7 CFR 319.40-
3(b) that address these risks. Further, on January 20, 1999, we
published in the Federal Register (64 FR 3049-3052, Docket No. 98-057-
1) an advance notice of proposed rulemaking soliciting public comment
on how to amend our regulations on the importation of logs, lumber, and
other unmanufactured wood articles to decrease the risk of solid wood
packing material (e.g., crates, dunnage, wooden spools, pallets,
packing blocks) introducing exotic plant pests into the United States.
We are currently reviewing the information received in response to that
notice and are preparing a risk assessment and other documentation
regarding the issue.
Comment: The eighth step in the risk assessment (pest able to
complete its life cycle) is likely to be the most uncertain of all,
certainly for the diseases, since so little is known of the population
biology of these diseases. For fruit flies, APHIS clearly recognizes
that a problem exists, but its attempt to take account of it (section
8.e. P8) is unfortunately incorrect and inadequate. It seems likely
that a better incorporation of concepts from population biology would
almost certainly change the model used in the risk assessment, at least
for the final step(s).
Response: Much is known about the population biology of the
diseases and fruit flies, and we believe that we took into account all
the pertinent aspects of the known biology of these plant pests in our
estimates for P8 for both the diseases and fruit flies. For the
diseases, we considered the type of infective propagules produced by
the pathogens and the environmental and physiological requirements for
host plant susceptibility and successful disease progression. For fruit
flies, we estimated the probability of an outbreak, per infested lot of
fruit fly host material, for infested lots delivered to suitable
habitats using data on the known number of Anastrepha outbreaks from
1990 through 1996 and estimates of the number of infested lots entering
favorable habitats in the United States.
[[Page 37653]]
The paper that forms the basis of those estimates (Miller et al. 1996,
cited in the risk assessment) was subjected to international review by
scientists conducting research on the population biology of fruit
flies. Thus, we believe that we did incorporate concepts from
population biology in our estimates for P8 for each of the diseases and
fruit flies, and do not believe that there are any pertinent aspects of
the known biology of these plant pests that were not considered in the
risk assessment.
Comment: The most difficult and least certain parts of the pathway
(the U.S. segment) are common to the mitigated and unmitigated
scenarios. It seems unlikely that incorporation of details of
population biology would make as large a difference for diseases as it
might for fruit flies, since it is unlikely that interactions between
fungal spores or colonies are as substantial as between individual
fruit flies. In such circumstances, it may be useful to perform a
differential analysis of the risks for diseases that will isolate just
the effects of the mitigation measures. In this case, a differential
analysis would stop at the calculation of the probability for infected
fruit to enter the United States, and so emphasize the relative effect
of the mitigation measures. This procedure has the effect of removing
the substantial uncertainties in the rest of the pathway from
consideration, since such uncertainties would be common to both
mitigated and unmitigated scenarios (unless, for some reason, there
were correlations connecting the Argentine and U.S. segments of the
pathways).
Response: Separate analyses were performed for the fruit flies and
the diseases. International guidelines, and APHIS interests, dictate
that the likelihood estimate of primary interest is the likelihood of
introduction, not the likelihood of entry. Nonetheless, it is possible
to calculate our estimates for the likelihood of entry using the
information provided in the risk assessment. Estimates for the
likelihood of entry could be obtained by using P5 as the endpoint of
the simulation and the values provided in Tables 7 through 10.
Regarding the issue of a differential analysis, it is not clear how
conducting a differential analysis to emphasize the relative effect of
the mitigation measures would aid APHIS' decisionmaking process. We
must consider the risk posed by the entire pathway. The decision of
whether to proceed with the rulemaking process is based on the risk
presented by the entire pathway.
Comment: In the current assessment, the known total mitigation
effect for citrus black spot (ratio of infection rates for fruit at the
U.S. in the unmitigated versus mitigated scenarios) is controlled
solely by the effect of the copper oxychloride treatment, and might
amount to a factor of 50 to 200-fold under the conditions of the
experiments available in the record. No evidence has been presented in
the record for any mitigating effect of the other proposed steps, and
there is evidence indicating a lack of effect for the post-harvest
treatments. The full system tests are entirely consistent with such
minimal effects, given the detection limits of those tests. Moreover,
there is no evidence that good results could be achieved consistently
over time, with fruit from different areas, with grapefruit, or with
different varieties of lemons and oranges. This minimal and relatively
unproved mitigation effect might be compared with the much higher and
well-proved 30,000-fold (probit 9) mitigation effect afforded against
fruit flies by cold treatment, although the absolute probability for
subsequent infection in the United States must also be taken into
account.
Response: It is not true, as stated by the commenter that ``the
known total mitigation effect for citrus black spot (ratio of infection
rates for fruit at the U.S. in the unmitigated versus mitigated
scenarios) is controlled solely by the effect of the copper oxychloride
treatment.'' Although the copper oxychloride treatment is the primary
risk mitigation measure against citrus black spot, other measures that
will have a mitigating effect on citrus black spot were identified and
discussed in the risk assessment; these measures are required by this
rule and thus will be applied consistently over time. Specifically, the
removal of debris prior to bloom is also an effective mitigation
measure in that it reduces inoculum present in the grove. Additionally,
the harvest and packinghouse culling reduces the likelihood that
diseased, symptomatic fruit will be shipped. It is correct that the
post-harvest treatments have little effect on citrus black spot. With
the inclusion of the 20-day preharvest incubation to detect latent
infection, whereby observation of a single infected fruit will remove
the entire grove from the export program for the entire year, the
overall systems approach results in a substantial risk reduction. Our
estimates of the risk reduction afforded by all these measures, and our
use of supporting data and expert judgment in arriving at those
estimates, are set forth in the risk assessment.
The commenter concludes by contrasting the 30,000-fold mitigating
effect of cold treatment for fruit flies with the smaller (50- to 200-
fold) effect of the mitigating measures for citrus black spot. Taken on
its face, this comparison would seem to indicate that the mitigating
measures for citrus black spot leave something to be desired in terms
of their ability to reduce the risk presented by that disease. However,
as is clearly presented in table 11 of the risk assessment, the
baseline (unmitigated) risk presented by citrus black spot is far lower
than that presented by fruit flies (in the mean, 1 chance in 28,653 for
citrus black spot versus 1 chance in 7.4 for fruit flies). Thus, even
with the comparatively more modest mitigating effect of the citrus
black spot measures, the risk estimated for citrus black spot in the
mitigated scenario is still lower than that estimated for fruit flies
(in the mean, 1 chance in 3.2 million for citrus black spot versus 1
chance in 350,000 for fruit flies).
Comment: APHIS does not have guidelines for performing quantitative
pest risk assessments. While such guidelines can, in many cases, be
restrictive and prevent development of better approaches, they can also
serve a useful purpose by preventing common errors. In view of the
myriad problems with the risk assessment, APHIS should consider
developing quantitative guidelines, in consultation with experts in
probabilistic risk assessment, to prevent similar problems in future
quantitative assessments.
Response: APHIS has published very specific guidelines for
qualitative plant pest risk assessments (USDA 1995, ``Pathway-Initiated
Pest Risk Assessment: Guidelines for Qualitative Assessments, version
4.0,'' USDA-APHIS-PPQ, Riverdale, MD). The only difference between the
methods described in that document and our probabilistic assessments is
section 8, where we estimate the likelihood of introduction. APHIS has
not published a separate document describing the methods it uses to
estimate the likelihood of introduction when using probabilistic
methods. Although our methods have evolved slightly with each
probabilistic assessment as we obtain comments, our methods have
remained fairly consistent and clearly illustrated. Additionally, the
methods we used in the present risk assessment are clear. Our process
was created in consultation with world leaders in the field of
probabilistic risk assessment, and our process has indeed been
subjected to extensive peer review by experts in probabilistic risk
assessment. Subsequent reviews by experts have been very favorable and
have led to several improvements in our process.
[[Page 37654]]
Although improvements will be made following the present risk
assessment, we have not been made aware of any significant errors that
require significant changes in our methods.
Risk Assessment--``Principles of Good Practice''
The following comments were generated by a commenter who evaluated
the risk assessment against 14 principles of good practice for Monte
Carlo risk assessment outlined by Burmaster and Anderson (1944). APHIS
is familiar with this publication, has referred to it often, and has
used it along with other similar works as a guide when conducting
probabilistic risk assessments. However, this particular work
represents only one set of suggestions and does not represent an
``industry standard.'' Despite that, as indicated in the individual
responses below, our methods are consistent with many of the
suggestions listed by the commenter. Below, we have presented each
principle and the accompanying critique provided by the commenter, and
each is followed by APHIS' response. Further, as discussed in the
introductory note to the previous section of this document (``Risk
Analysis''), additional documentation regarding the information or data
used as the basis for the risk assessment's conclusions is contained in
an addendum to the risk assessment that may be obtained from the person
listed under FOR FURTHER INFORMATION CONTACT.
Show all formulas used in the risk assessment. We do not agree with
the structure of the model used in the risk assessment. However, the
only formula used in the APHIS risk assessment is the simple
multiplicative formula used to calculate the likelihood of pest
establishment. This formula is simple and, while not presented
algebraically, is presented in Figure 2 and adequately described in the
text. However, Figure 2 is illegible, even in the electronic version of
the report available on the Internet, due to the extremely low
resolution of the image file. No better copy is available anywhere in
the risk assessment or in the rulemaking record.
Response: As indicated by the commenter, our risk assessment is
quite transparent. We explained in extensive detail how we conducted
our risk assessment, and we and our peer reviewers have found the
structure of our model to be appropriate and correct. We apologize if
the commenter had difficulty downloading material from our web site and
we would be happy to provide additional copies of our model. APHIS
regularly supplies paper copies of the risk assessment to anyone
requesting a copy.
Calculate and present point estimates of risk. APHIS does not
calculate a point estimate of the risk of infestation; however, this
principle is not necessarily applicable to a plant pest risk
assessment. In a human health risk assessment, such a point estimate
provides a point of comparison for the results of the Monte Carlo
analysis with standard analyses that are familiar. In a plant pest risk
assessment, a point estimate would be somewhat less useful since
quantitative point estimates are as unfamiliar as probabilistic
estimates, and so may not be necessary.
Response: We agree with the commenter's sense that point estimates
are not a necessary element of a plant pest risk assessment, which is
why we did not calculate a point estimate of the risk of infestation.
Present the results from sensitivity analyses to identify inputs
suitable for probabilistic treatment. APHIS does not perform
sensitivity analyses or analyze inputs to determine how given variables
affect the predicted risk. As mentioned previously, many of the
distributions used in the risk assessment are not based on measured
data. A sensitivity analysis could be used to help focus data
collection on the most important variables. Additionally, such an
analysis could identify variables that drive the risk assessment in two
senses: (1) Variables that account for the magnitude of the predicted
risks and (2) variables that account for the range of the predicted
risks. Understanding which variables drive the resulting risk
distribution in these two senses is key to interpreting the results of
the risk assessment and focusing future research.
Response: We did perform sensitivity analyses as part of the final
step of the probabilistic analysis of the proposed mitigation program;
as the earlier steps in the risk assessment were not probabilistic,
sensitivity analyses were not performed on those earlier steps.
Further, because sensitivity analyses are not particularly useful with
a simple, linear, multiplicative model of the type used in the risk
assessment, they were not discussed in the risk assessment. If the
commenter is interested, our sensitivity analyses are part of the
documentation contained in the supplemental information that is
available from the person listed under FOR FURTHER INFORMATION CONTACT.
The commenter suggests that sensitivity analysis could be used to
help focus data collection on the most important variables, but that
was not the purpose of the risk assessment. Rather, the purpose of the
risk assessment was to estimate the risk associated with a particular
proposed program, and not to aid in the design of a new program.
The commenter also suggests that: ``Additionally, such an analysis
could identify variables that drive the risk assessment in two senses:
(1) Variables that account for the magnitude of the predicted risks and
(2) variables that account for the range of the predicted risks.
Understanding which variables drive the resulting risk distribution in
these two senses is key to interpreting the results of the risk
assessment and focusing future research.'' Regarding item (1), the risk
assessment discusses mitigations that reduce risk, and it provides
estimates of the likelihood of pest introduction with and without the
system of risk mitigations. The various input parameters do not
represent sources of risk per se, they represent events that must occur
before a pest can be introduced; some of them represent specific risk
mitigations (e.g., P5, cold treatment for fruit flies), not sources of
risk, while others reflect the biology of the organism and are not
sources of risk (e.g., P7, pest locates suitable host). The sources of
risk are identified in the hazard identification section of the
assessment (Sections 4-6).
Regarding item (2), the sensitivity analyses we conducted do in a
sense identify ``variables that account for the range of the predicted
risks,'' but the commenter's wording does not reflect the purpose,
outcome, or use of the risk assessment. The risk assessment does not
deal with a ``range of predicted risks.'' The probabilistic portion of
the risk assessment estimates, for four separate pests, the likelihood
of introduction given importations with no specific risk mitigations
(the baseline scenario) and with a specific set of mitigations (the
proposed program). However, our sensitivity analyses do indeed identify
those variables that account for the largest amount of uncertainty in
the output (the estimated likelihood of pest introduction). As noted
earlier, with the type of model used in the risk assessment (i.e.,
simple, linear, and multiplicative), that information can be obtained
by examination of the input parameters (Tables 7-10).
Restrict the use of probabilistic techniques to issues of
regulatory importance. The APHIS risk assessment is restricted to the
issue of regulatory importance, i.e., the likelihood that exotic pests
imported with Argentine produce will establish themselves in the United
States. There are few enough parameters in the model that probabilistic
techniques can be used on
[[Page 37655]]
all. A more realistic model (e.g. including failure modes and
correlations) might, however, be too complex for such an approach
(particularly using the chosen software).
Response: We agree that our model is appropriate to the task at
hand. We disagree that a more complex model would necessarily be more
realistic; thus, we see no reason to needlessly complicate our model.
Provide detailed information on the input distributions selected.
APHIS presents the parameters necessary to characterize the
distributions used in the risk assessment. It also, and unnecessarily,
presents the mean, mode, standard deviation, 5th percentile, and 95th
percentile of most distributions, at great length and repetitively in
the text. This allows an informed reader to reproduce the calculations.
APHIS, however, provides very little additional information about the
distributions it selected. It presents no graphs of the distributions
used in the assessment. Very little justification is provided for the
choice of distributions in the report beyond ``expert judgment,'' so
that even knowledgeable persons cannot reproduce the full analysis. For
some distributions, APHIS identifies data that can be used to support
the distribution (such as for sweet orange scab incidence), but offers
no justification for the type of distribution selected and no
description of how the data are used to construct the distribution.
Response: We agree that the information we provided was sufficient
to allow an informed reader to reproduce our calculations. We did not
present graphs for a variety of reasons, not the least of which is that
graphs would be redundant. However, an informed reader could produce
graphs of our distributions using the information provided in the risk
assessment. We believe we included sufficient information about the
generation of our input distributions in the narrative descriptions
that are provided in the risk assessment for each of the input values
(F1, P1 through P8) used in our likelihood model. If the commenter is
interested, expanded explanations regarding our selection of input
distributions are part of the documentation contained in the
supplemental information that is available from the person listed under
FOR FURTHER INFORMATION CONTACT.
Show how the input distributions capture and represent both the
variability and the uncertainty in input variables. APHIS makes no
effort to distinguish between variability and uncertainty, and offers
no discussion of their separate contributions to the results of the
analysis. The roles played by uncertainty and variability in the risk
assessment depend on the goal of the analysis. If the goal of the
analysis is to estimate a distribution for the average annual
likelihood that an infestation will occur in the United States,
uncertainty will play a larger role in the analysis than variability.
Year-to-year variability may be intentionally ignored in the analysis
because the analysis would not be focusing on variations in the
likelihood of an infestation from year to year. If, instead, the goal
of the analysis is to generate a distribution of the likelihood that
each box of fruit will cause an infestation, year-to-year variability
may play a much larger role. The goal of the analysis should be more
clearly defined, and APHIS should include a discussion of the roles of
uncertainty and variability in the analysis.
Response: The approach suggested here is relatively new and is
appropriate only in certain situations. In other situations, such as
the present risk assessment, it is not clear that better results would
be obtained. In fact, using this approach would require a significant
overinterpretation of available data and would most likely lead to risk
estimates that are less, rather than more, accurate. When making a
decision about whether to allow importation of a particular commodity,
whether uncertainty in the estimate results from variability or other
forms of uncertainty may not matter. The primary consideration is the
value of the risk, not the shape of the output distribution.
The purpose of our analysis is closer to the first of the possible
goals suggested by the commenter (``to estimate a distribution for the
average annual likelihood that an infestation in the United States'')
than it is to the second (``to generate a distribution of the
likelihood that each box of fruit will cause an infestation'').
Specifically, in section 8 of the risk assessment, we state: ``The
purpose of a probabilistic risk assessment is to estimate the
likelihood of an undesirable outcome (bad event). The bad event is
represented by the endpoint of the risk model, i.e., introduction of a
quarantine pest.''
Use measured data to inform the choice of input distributions
whenever possible. As noted above, most of APHIS's distributions are
based on expert judgment. The risk assessment includes little
discussion of the reasoning behind the selection of distribution type
and the parameters used to characterize the distributions. In some
cases, APHIS identifies available data, but it is not clear how these
data are used in the construction of the distribution.
Response: We did, in fact, use measured data whenever possible to
inform our choice of input distributions when preparing the risk
assessment. Ideally, existing data would provide the basis for direct
estimation of model inputs; however, when conducting probabilistic
assessments to inform decisions regarding importation of agricultural
commodities, scientific experiments have not, except in rare cases,
been conducted that provide data that represent ``direct evidence'' for
risk assessments. In fact, results are seldom provided that can even be
used as indirect model inputs. As we made clear in the risk assessment,
all available data were reviewed and professional judgment then used to
represent the available information. Because most of our commodity risk
assessments are conducted to support decisions that must be made within
relatively narrow time frames, research programs can seldom be designed
and conducted to provide data specifically for the assessments
(although in the present case, the United States required Argentina to
design and conduct additional experiments that were completed before
completion of the risk assessment). Beyond directly applicable measured
data, USDA bases the estimates needed for its probabilistic commodity
risk assessments on pest interception records, the known biology of the
organism being assessed (or the known biology of related taxa) as
represented in the scientific literature, expert judgment based on
laboratory experience with the pest or related organisms, expert
judgment based on field experience with the pest or related organisms,
expert judgment based on experience conducting commodity inspections at
ports of entry or in the exporting country, and experience working with
export programs and export-quality commodities.
Discuss the methods and report the goodness-of-fit statistics for
any parametric distributions that were fit quantitatively to measured
data. It is not clear from the text of the report whether APHIS
actually fits distributions to any real data. No goodness-of-fit
statistics are reported in the assessment. There is no discussion of
any relation between the cited experts' estimates of minimum, maximum,
and mode, and the parameters of the distributions, nor is such a
relation self-evident. If the data fitting algorithms in @Risk were
used to fit distributions to data, the procedure should be clearly
described in the text.
robop...@us.govnews.org
Posting-number: Volume 65, Issue 116, Page 37607, Part 1
[[Page 37624]]
we do not believe that any of those taxonomic issues need to be
resolved in order for the survey, inspection, and treatment provisions
of this rule to be effective in reducing the risk of sweet orange scab
being introduced into the United States.
Comment: A more detailed description of how an orchard will be
inspected or sampled (location in grove, timing, etc.) for sweet orange
scab is necessary.
Response: The freedom of the fruit from sweet orange scab will be
verified through the inspections required by this rule, i.e., the
visual inspection of the grove and buffer area required by Sec. 319.56-
2f(b)(6) and the packinghouse inspections required by Sec. 319.56-
2f(c)(4) and (c)(5). Given that the symptoms of sweet orange scab are
readily detectable on infected fruit, and given that the detection of
the disease in a single fruit will result in a grove's losing its
ability to export fruit to the United States for the remainder of the
current growing and shipping season, we believe that the 20-day
preharvest survey and the subsequent packinghouse inspections will
effectively mitigate the risk of fruit infected with sweet orange scab
being imported into the United States.
Comment: Copper-based fungicides are preventative, i.e., they only
prevent new infections and do not stop already established infections.
Thus, timing is extremely critical to ensure that developing fruit is
continuously protected from infections. Other fungicides, such as
preharvest applications of Benomyl (benlate), not only prevent, but
also stop infections that are already present, and newer chemistry
fungicides (triazoles, strobilurins, etc.) may provide better control
of already infected fruit and allow rotation of fungicides.
Response: Copper oxychloride is a well-established preventative
treatment for citrus black spot and sweet orange scab, and its efficacy
has been demonstrated in a variety of studies on the control of these
diseases (for example, as referenced in Whiteside et al., 1988, as
cited in the risk assessment). We would, however, certainly consider
allowing the use of other fungicides if the Argentine growers or SENASA
were to request that we do so and were to provide information
supporting the efficacy of the alternative treatments.
Comment: Since the packinghouse treatments have little or no impact
on citrus black spot infections, any citrus black spot present in the
fruit must have been prevented or detected by the time of harvest. The
keys to the proposed program for Argentina are successful prevention
and successful detection of any infection. The proposed preventative
fungicide treatments are not 100 percent effective, so the successful
detection of treatment failures is critical, but the latency of citrus
black spot makes that detection very difficult. Given that difficulty,
it appears there is a near certainty that latently infected fruit will
be imported into the United States.
Response: As explained in detail later in this document, we have
modified the protocol for sampling the grove and buffer area in
response to comments on the subject. This final rule requires the
sampling of 4 fruit from each of 298 randomly selected trees in each
800 hectares of grove and buffer area, which yields at least a 95
percent confidence level of detecting an infection rate of 1 percent or
greater. In addition, the modified sampling protocol requires that the
fruit be chosen from the portion of the tree most likely to have
infected fruit. Given those requirements, there is almost no chance
that infection could exist in a grove without infected fruit being
included in the sample subjected to laboratory examination. Further,
during the required 20-day sample holding period, the fruit will be
held under conditions that are ideal for the expression of symptoms in
any infected fruit (i.e., 27 deg.C, 80 percent relative humidity, and
permanent light). Finally, this rule requires that the detection of
symptoms in a single fruit will result in a grove being removed from
the export program and all fruit from that grove being prohibited from
entering the United States. Given those considerations, we believe that
the risk of latently infected fruit being imported into the United
States is negligible.
Comment: The risk assessment claims the buffer zone receives the
same ``treatment, inspections, sanitation, etc.'' as the grove, but the
proposed rule only calls for full inspections of fruit from the grove,
not from the buffer zone. Thus if citrus black spot or sweet orange
scab is detected on fruit from the buffer zone at or after harvest,
there is strictly no requirement to remove that grove from the program.
Indeed, there are no requirements in the proposed rule for any
inspection or reporting on diseases in the buffer zone after the 20
days preharvest inspection.
Response: This final rule, as did the proposed rule, calls for the
removal of fallen fruit, leaves, and branches from both the grove and
the buffer area, inspection of both the grove and the buffer area to
ensure the cleaning requirements have been met, spraying of oil-copper
oxychloride in both the grove and the buffer area, and a visual
inspection of both the grove and the buffer area 20 days before
harvest. While the proposed regulations did not specifically state
where the sample of fruit for laboratory examination was to be
collected, the samples must be taken from both the grove and the buffer
area. (This is made clear in Sec. 319.56-2f(b)(6)(ii) in the regulatory
text of this final rule.) This is consistent with the risk assessment's
statement that the buffer zone will receive the same ``treatment,
inspections, sanitation, etc.'' as the grove. After harvest, the
packinghouse treatments and inspections are limited to the fruit from
the grove itself because, as stated in Sec. 319.56-2f(b)(2), no fruit
from the buffer zone may be offered for importation to the United
States.
Comment: There is no definition of ``laboratory,'' or any
requirement for certification of such laboratories, nor is there any
requirement that the laboratory examination be certified or carried out
by SENASA.
Response: The laboratory testing required by Sec. 319.56-
2f(b)(6)(ii), as is the case with the other surveys and inspections
that must be conducted in Argentina under this rule, must be conducted
under the direct supervision of SENASA, and records relating to testing
and test results will be available for review by APHIS.
Post-harvest Requirements
Comment: The risk assessment (8.a.) claims that packinghouses will
be used for export to the United States only. The preamble of the
proposed rule states that packinghouses cannot accept fruit from
``nonregistered export groves during the time that fruit intended for
export to the United States is being handled in the packinghouse.'' The
proposed rule requires that ``[d]uring the time that a packinghouse is
used to prepare grapefruit, lemons, or oranges for export to the United
States, the packinghouse may accept fruit only from groves that meet
the requirements of paragraph (b) of this section.'' The risk
assessment (8.a.) requirement is stricter than the proposed rule, and
the preamble of the proposed rule indicates that packinghouses could
accept nonregistered, nonexport fruit. The proposed rule allows for
some possibility of admixture, since no time-scale is specified; one
could alternately process nonexport and export fruit in separate
batches.
Response: While the risk assessment's narrative description of the
systems approach and the proposed rule's description of packinghouse
requirements differed in their approach,
[[Page 37625]]
we do not believe that the two documents contradict one another. The
statement in the risk assessment that packinghouses in the program will
only be used for export to the United States reflected the risk
assessors' understanding that there would be no commingling of fruit
from registered and nonregistered groves in the packinghouses. This is
entirely consistent with our statement in the preamble of the proposed
rule that ``[b]arring the entry of fruit from nonregistered groves into
the packinghouse would ensure that the fruit intended for export is not
commingled with or potentially infected by fruit that was grown in a
grove that has not been subject to the same sanitation, inspection, and
treatment measures that would be required for export groves.'' This
statement from the proposed rule's preamble also makes it clear that we
were not indicating, as the commenter asserts, that packinghouses would
be able to accept fruit from nonregistered groves during the time that
fruit was being prepared for export to the United States.
To address the commenter's concerns that ``no time-scale is
specified'' with regard to when batches of export fruit and nonexport
fruit could be processed, we have modified the wording in Sec. 319.56-
2f(c)(2) to reflect our intent that there be no commingling of fruit
from registered and nonregistered groves in the packinghouse. That
paragraph now states: ``During the time that any grapefruit, lemons, or
oranges from groves meeting the requirements of paragraph (b) of this
section are in the packinghouse, no fruit from groves that do not meet
the requirements of paragraph (b) of this section may enter the
packinghouse.'' To support this requirement, and to prevent the
``possibility of admixture'' raised by the commenter, a SENASA-
registered technician will be present at each packinghouse to verify
the origin of all fruit entering the packinghouse. In its
correspondence with APHIS during the development of the proposed rule,
SENASA had stated that a registered technician would be present at each
packinghouse for that purpose, but this consideration was not
explicitly set forth in the text of the proposed rule. We also are
amending Sec. 319.56-2f(c)(2) to make it clear that a packinghouse
technician registered with SENASA must verify the origin of all fruit
entering the packinghouse.
Comment: What steps will be taken to ensure there is no commingling
of fruit from certified and uncertified groves at the packinghouse? For
example, records would have to be kept of the arrival of each load.
These records would have to be available for auditing.
Response: As noted in the response to the previous comment, a
technician responsible for the packinghouse, who will be approved by
and registered with SENASA, will be on hand to verify the origin of all
lots of fruit entering the packinghouse. These technicians are required
by SENASA to maintain accurate records, and SENASA will make those
records available to APHIS upon request.
Comment: The proposed rule and risk assessment do not mention the
need for measures to prevent the contamination of export groves,
packinghouses, or storage facilities by workers or equipment that have
been in untreated groves or that have been in contact with untreated
fruit. Such measures are necessary to prevent the artificial spread of
disease inoculum. APHIS should consider establishing sanitation
measures for workers and equipment moving between nonregistered groves
and those producing fruit destined for export to the United States. The
requirements would have to be set forth in detail in the regulation,
and strict audit and inspection procedures would have to be implemented
to ensure that disease is not transmitted to export groves. If such
requirements are not established, APHIS should discuss why such
measures are not needed, given the characteristics of the two diseases
of concern. Similarly, APHIS should establish sanitation measures for
packinghouses and storage facilities to use between runs of U.S.-bound
citrus and fruit bound for other markets.
Response: The spores produced in fruit infected with sweet orange
scab and citrus black spot are nonpigmented and are thus short-lived
when removed from their host tissue. It is, therefore, unlikely that
any ``free'' spores that might be found on workers or equipment moving
from an untreated grove into an export grove, packinghouse, or storage
facility would remain viable long enough to cause infection. Similarly,
because of the short-lived nature of ``free'' spores, there is little
risk that export fruit would become contaminated during processing at a
packinghouse that had previously handled fruit from nonregistered
groves. In any event, that export fruit will be mature fruit, and thus
not susceptible to infection. Furthermore, that fruit will be surface-
sterilized and waxed in the final processing steps before being packed
in boxes, thereby rendering nonviable any spores contaminating the
surface of the fruit. That surface-sterilization and waxing is a
routine measure applied to all fruit in Argentine packinghouses,
including nonexport fruit, so it is unlikely that export fruit would be
contaminated after packing even if it was stored with nonexport fruit.
Comment: The proposed rule does not specify what happens to other
fruit in the packinghouse if infected fruit from some other grove that
simultaneously or recently went through the same packinghouse is
detected.
Response: We believe that it is unlikely that infected fruit would
proceed undetected as far as the packinghouse, given this rule's
requirements for the removal of potential sources of inoculum from the
groves, the treatment of developing fruit, and the sampling and testing
of mature fruit prior to harvest. However, if infected fruit was
identified in the packinghouse or at a later time, we believe that the
non-susceptibility of the mature fruit that will be handled in the
packinghouses, when combined with the short-lived nature of ``free''
spores and the required surface-sterilization and waxing, make it
unlikely that fruit will be contaminated as a result of contaminated
fruit having recently passed though the same packinghouse. This rule's
requirement that the identity of the origin of the fruit be maintained
during its time in the packinghouse will prevent fruit from two
different groves being processed simultaneously.
Comment: The risk assessment claims that at the prepacking
inspection stage, any blemished fruit are culled. There is no
requirement in the proposed rule for culling of blemished fruit,
although that presumably would be a commercial necessity; the proposed
rule only requires SENASA to examine fruit for any evidence of disease.
Response: The commenter is correct in presuming that the culling of
blemished fruit is a commercial consideration. As such, our proposed
rule did not include a requirement for the culling of blemished fruit,
per se, but instead focused on SENASA inspecting the fruit prior to
packing to verify its freedom from citrus black spot and sweet orange
scab. However, as explained in the response to the next comment, we
have included the culling of blemished fruit in the provisions of this
rule set forth in Sec. 319.56-2f(c)(4) relating to the 4-day
packinghouse holding period.
Comment: The proposed rule called for the holding of all harvested
fruit for 4 days at room temperature before sorting and packing, but
there is no evidence in the record that this is an adequate time for
latent citrus black spot symptoms to develop. The Argentine researchers
stated that they held sampled fruit for 20 days at 27 deg.C,
[[Page 37626]]
80 percent relative humidity, and in permanent light in order for
latent citrus black spot infections to develop enough for detection. In
addition, the risk assessment assumes that the fruit sampled from the
orchard shortly before harvest will be held for 20 days at room
temperature, which would allow latent citrus black spot infections to
show up in the samples. However, the proposed regulations do not
explicitly state a 20-day holding period at room temperature, nor do
they define what constitutes ``room temperature.'' APHIS should conduct
studies to determine the optimum time, temperature, and other
environmental conditions for detection of the latent citrus black spot
infections; if APHIS cannot provide data that demonstrates the
effectiveness of the 4-day holding period, a longer holding period
should be required. Further, steps must be taken to ensure that all
packinghouses are able to hold the harvested fruit at the required
temperatures for citrus black spot development in order to assess the
practicability of this measure. Finally, the requirements for Argentine
citrus should explicitly state that fruit sampled from the grove 20
days before harvest must be held under conditions conducive to citrus
black spot development.
Response: We acknowledge that the proposed rule did not fully
explain the procedure to be used during the 20-day laboratory
examination period of the sampled fruit. We further acknowledge that
the proposed rule incorrectly stated that the purpose of the 4-day
holding period was to allow for symptom expression of citrus black spot
in the event that latent infection exists in the fruit. We have
corrected both of these issues in the text of the final rule.
As noted by the commenter, the laboratory procedure to be used to
promote the expression of symptoms in the fruit sampled 20 days prior
to harvest will be to hold the fruit for 20 days at 27 deg.C, 80
percent relative humidity, and in permanent light. These conditions
have been shown to be ideal for latent citrus black spot infections to
develop enough for detection. Although this protocol was omitted from
the proposed rule, the protocol was, as evidenced by the commenter's
remarks, explained fully in documents made available following the
publication of the proposed rule.
If none of the sampled fruit manifest symptoms of citrus black spot
during the 20-day laboratory examination period, the remaining fruit in
the grove will be harvested and taken to the packinghouse, where it
will be held at room temperature--i.e., not refrigerated--for 4-days.
This 4-day holding period is a standard practice in the Argentine
citrus industry that provides sufficient time for bruises or other
damage on the fruit to become plainly evident, thus providing an
opportunity for that blemished fruit to be culled. For the purposes of
this rule, that 4-day holding period will also provide an opportunity
for SENASA inspectors to examine the harvested fruit for signs of
infection.
We have, therefore, amended the requirements set forth in the rule
portion of this document in order to fully explain these requirements.
The requirements pertaining to the laboratory examination are set forth
in Sec. 319.56-2f(b)(6)(ii), and the provisions relating to the 4-day
holding period and the culling of damaged fruit in the packinghouse are
set forth in Sec. 319.56-2f(c)(3) and (c)(4).
Comment: Section 8.a of the risk assessment claims 4-5 days holding
time (for all fruit) to allow expression of citrus black spot. Section
8.f P3 of the risk assessment claims a ``20-day preharvest sample and
incubation period'' that may have been derived from the 20-day
preharvest inspection, or may be a confusion between inspection and
this packinghouse holding time. Section 8.f P3 of the risk assessment
also confuses matters since it refers to a ``sample'' holding time, but
then refers to the likelihood of packinghouse detection, but the fruit
in the packinghouse would not have had the 20-day holding time. The
preamble and proposed rule require just 4 days holding time at room
temperature, followed by SENASA inspection.
Response: The commenter has identified that, like the proposed
rule, the risk assessment's narrative description of the systems
approach (Section 8.a) incorrectly characterizes the purpose of the 4-
day holding period. The intended purpose of both the 4-day holding
period and the 20-day laboratory examination period are explained in
the response to the previous comment and in paragraphs (b)(6), (c)(3),
and (c)(4) of Sec. 319.56-2f in this final rule. In light of that
explanation, it can be seen that the reference to ``a 20-day preharvest
sample and incubation period'' in section 8.f P3 of the risk assessment
accurately portrays what is required by this rule. Section 8.f P3 of
the risk assessment links the sample holding time and the likelihood of
packinghouse detection (which the commenter states ``confuses
matters'') because that node P3, ``Pathogen not detected at packing
house inspection'' is the portion of the risk assessment where the 20-
day holding period is addressed. As stated in Section 8.f. P3: ``Also
considered in making our estimates for this node in the mitigated
scenario, was the orchard sampling 20 days prior to harvest and the
incubation of this sample at room temperature to observe post harvest
symptom development.''
Comment: The risk assessment claims in section 8.a that blemished
fruit are culled during harvest and claims in section 8.f. P2 that
diseased fruit would be detected and culled at harvest; section 8.f P2
also stated that this detection would be improved for citrus black spot
``under the proposed workplan'' due to its ``more rigorous export
standards and [the] reduced frequency of latent infection,'' although
no specific measures are mentioned for harvest time. The preamble and
proposed rule have no harvest requirements whatever, and it appears
from the correspondence on the record that the Argentines do not know
what ``blemished fruit'' means.
Response: As noted in our response to a previous comment, the
culling of blemished fruit was not specifically addressed in the
proposed rule, but requirements for the culling of blemished fruit in
the packinghouse have been added to this rule. While pickers can be
expected to cull obviously blemished fruit during harvest, the best
opportunity for the removal of blemished fruit will come after the
fruit has been held for 4 days at room temperature. Given that the 4-
day holding period will provide an opportunity for bruises and other
damage on the fruit to become more readily apparent, we consider this
post-harvest culling to be an improvement over the reliance on pickers
to cull blemished fruit that was envisioned in the risk assessment.
Finally, we have explained to SENASA what we mean by the term
``blemished fruit.''
Comment: The proposed systems approach envisions chemical treatment
after the 4-day holding period, followed by a further inspection before
packing. Does APHIS believe such treatment will have any impact on
citrus black spot? If so, what is the evidence? The literature on
citrus black spot would indicate that such treatment would have no
impact. We believe that the data provided by Argentina demonstrates the
chemical treatment envisioned in the proposed systems approach, to be
applied prior to packing of the fruit, will not have any impact on the
virulence of the citrus black spot spores.
Response: The post-harvest treatment is designed to render
nonviable any spores contaminating the surface of the fruit, and these
post-harvest treatments
[[Page 37627]]
are mainly to prevent post-harvest decay. In the risk assessment, our
estimates took into account the fact that post-harvest treatments have
little effect on citrus black spot infections (a reduction from 0.64 to
0.50).
Comment: The proposed rule does not specify any concentrations or
other conditions for the immersion in orthophenilphenate of sodium, nor
any application rate for the spray with imidazole or application of 2-4
thiazalil benzimidazole and wax. Thus, it appears that any
concentrations or application rates--including ineffective ones--would
meet the requirements of the proposed rule.
Response: Argentina's environmental protection authority, like our
Environmental Protection Agency, requires that products such as those
called for in this rule be applied in accordance with their label
instructions. For orthophenilphenate of sodium, the concentration is
200 L per 2,000 L of water; for imidazole, it is 200 cm\3\ per 100 L of
water; and for 2-4 thiazalil benzimidazole, it is 0.5 L per 200 L of
water. By not including these concentrations in the text of the rule
itself, we avoid the need for future amendments to the rule should the
label instructions change.
Comment: The risk assessment (8.f. P4) states that the treatment
program incorporates a dip in 200 parts per million sodium hypochlorite
for 2 minutes. The preamble and rule portions of the proposed rule
spell out the required chemical treatments, but do not include any
mention of time for the sodium hypochlorite immersion.
Response: The commenter is correct; the proposed rule should have
stated that the immersion in sodium hypochlorite be for 2 minutes as
described in the risk assessment. We have corrected that omission in
Sec. 319.56-2f(c)(4)(i) of this final rule.
Comment: There is no explicit mention that the packed boxes of
fruit may not contain any plant parts other than the fruit to be
exported. Leaves and twigs are suitable vectors for diseases and
several insects pests (e.g., brown citrus aphid). While a prohibition
on inclusion of leaves, twigs, or other plant parts in packing boxes is
included as a general requirement for imported fruits and vegetables in
7 CFR 319.56-2(a), the requirements for Argentine citrus should
explicitly prohibit any plant parts other than the fruit itself.
Response: The commenter is correct in noting that Sec. 319.56-2(a)
requires that ``[a]ll importations of fruits and vegetables must be
free from plants or portions of plants, as defined in Sec. 319.56-1.''
Plants or portions of plants is defined in Sec. 319.56-1 as ``[l]eaves,
twigs, or other portions of plants, or plant litter or rubbish as
distinguished from clean fruits and vegetables, or other commercial
articles.'' We agree that this is an important requirement and have
added language to the requirements in Sec. 319.56-2f(c)(5) to make it
clear that SENASA inspectors must ensure that all stems, leaves, and
other portions of plants have been removed from the fruit prior to
packing.
Comment: All packing boxes sent to commercial citrus-growing areas
of the United States should be required to be destroyed upon reaching
their destination, and records of such destruction should be kept.
Response: We are unaware of any risks presented by packing boxes
used to ship citrus fruit produced in accordance with this rule that
would make it necessary to require their destruction, and we do not
believe that any meaningful reduction in risk would be realized by
imposing such a requirement.
Fruit Flies, Other Pests, and Treatments
Note: On May 19, 2000, we received a letter from the California
Citrus Research Board (CCRB) informing APHIS that the CCRB had
contracted with U.S. Department of Agriculture's (USDA's)
Agricultural Research Service (ARS) to conduct a research program to
determine the suitability of lemons as a host of tephritid fruit
flies. The CCRB letter reported that the preliminary results of the
initial tests call into question the current regulatory assumption
that lemons at any stage of maturity are not a viable fruit fly
host. When contacted by APHIS for additional information, ARS
reported that the preliminary results were similar to the results
published in 1984 by ARS scientists (i.e., the Spitler, et al.
research discussed below) in which a limited number of Medfly pupae
were recovered in similarly conducted tests. ARS reports that, at
the present time, it is reluctant to extend the findings of these
preliminary laboratory cage studies to lemons in a commercial field
setting where there might be other, more preferred fruit fly hosts
present. Further, ARS points out, some species of fruit are known to
be much more infestable after harvest than before as a result of a
rapid ripening process initiated when the fruit is separated from
the tree; ARS states that fruit that can be stored on the tree, such
as citrus, may fall into this category. ARS has stated that they
will provide APHIS with a full report upon the conclusion of the
studies. If the results of the studies lead to a recommendation that
quarantine measures such as cold treatment should be required for
lemons, we will take action to amend both our foreign and domestic
quarantine regulations to require that the appropriate treatment be
applied to lemons as a condition of importation or interstate
movement.
Comment: APHIS should require a fruit fly trapping program in the
export area and should require spraying of the groves if population
levels exceed a set threshold. If the spraying proves ineffective at
eradicating the fruit flies, exports should be cut off, even with cold
treatment.
Response: Argentina reports that populations of Medfly and the
South American fruit fly (Anastrepha fraterculus) are not present at
economically important levels and periodically confirms their low
population levels through trapping. Further, Argentina maintains that
A. obliqua and A. serpentina are not present in Argentina despite
reports to the contrary, and that both species of fruit fly are
considered quarantine pests in Argentina. Given the economic importance
of the citrus industry in Argentina, it is in that country's best
economic interests to ensure that fruit fly populations remain low. The
lack of significant fruit fly population pressure, combined with the
nonhost status of smooth-skinned lemons and this rule's requirement for
a probit 9 level (99.997 percent mortality or 1 survivor per 33,333)
cold treatment for grapefruit, oranges, and lemons other than smooth-
skinned lemons, has led us to conclude that trapping and spraying
provisions are not a necessary element of the Argentine citrus export
program.
Comment: There is no discussion in the proposed rule of fruit fly
detection in Argentina, nor what, if any, prevalence of fruit flies
would be sufficient to prevent import. Thus, any analysis must take
account of the possibility of very high prevalence of fruit flies.
Response: Our risk assessment did take into account the presence of
fruit flies in Argentina and concluded that the nonhost status of
smooth-skinned lemons and the post-harvest cold treatments for other
citrus fruit would reduce the risk of Argentine citrus introducing
fruit flies into the United States to a negligible level.
Comment: The proposed rule, the risk assessment, and the PPQ
Treatment Manual (which is used by APHIS personnel as a guide for the
application of quarantine treatments) do not consider the issue of
``preconditioning phenomenon,'' which could render cold treatment
ineffective in preventing the transmission of fruit fly pests into the
United States via Argentine citrus. Research indicates that fruit fly
larvae and eggs can develop increased tolerance to quarantine cold
treatment if the infested fruit is exposed to sublethal temperatures in
the field or in storage prior to the initiation of an approved cold
treatment. In order to preclude the possibility of preconditioning
[[Page 37628]]
phenomenon, the PPQ Treatment Manual should explicitly state that the
fruit should not be held at sublethal chilling temperatures prior to
initiation of cold treatment. In addition, further research should be
conducted to determine whether it may be necessary to require fruit
subjected to cold field or storage conditions to undergo longer
quarantine chilling periods.
Response: In a publication titled Temperature Sensitivity in
Insects and Application in Integrated Pest Management (edited by Guy J.
Hallman and David L. Denlinger, Westview Press, 1998), it is noted that
any technique used to reduce chilling injury (e.g., holding the fruit
for several days at temperatures several degrees above the quarantine
treatment temperature, which is referred to as ``pretreatment'' or
``preconditioning'') can also be suspected of favoring the survival of
the pest inside the fruit. However, Dr. Guy Hallman, one of the editors
of that publication, indicated to APHIS that no references in the
literature were found for this ``preconditioning phenomenon'' with
regard to quarantine pests, although it has been demonstrated with
flesh flies, house flies, Drosophila, and other laboratory species. It
was Dr. Hallman's opinion that because cold treatments are so extreme
and infestation rates in commercial fruit are so low, the issue of
``preconditioning phenomenon'' is not likely to be a serious practical
concern. This opinion is borne out by the consistently successful use
of quarantine cold treatments around the world over many years on
numerous commodity/pest combinations.
Comment: APHIS's position that lemons cannot be a host to
Mediterranean fruit fly is not consistent with published scientific
literature on the subject, which demonstrates clearly that lemons can
become a host to this pest in certain circumstances. While lemons are
not a preferred host to the Medfly, they have been found to be a host
when insect pressure is applied to ripe or damaged fruit. If tree-ripe
fruit is shipped to the United States, this increases the risk of
Medfly introduction into the United States dramatically. The studies
APHIS cites to support the nonhost status of lemons (Spitler et al.
1984) are based on lemons picked green to partially ripe, which is how
lemons are picked in commercial production in the United States. It is
not clear from the proposed rule at what stage the Argentine lemons
will be picked for export to the United States, but we believe the
Argentines pick lemons by maturity, since much of their fruit goes to
processing and currently they do not have the ``curing'' facilities to
ripen lemons during storage. APHIS should establish maximum maturity
standards for lemons for export, in the absence of cold treatments. If
the maturity standard is exceeded, then either a cold treatment should
be required or the shipment of ripe lemons should be rejected for
export. Further, APHIS needs to consider the impact of harvesting
lemons at earlier stages on the ability to detect any citrus black spot
infections.
Response: While the commenter refers to lemons in general, it is
only smooth-skinned lemons that are exempted from the cold treatment
requirements of this rule. In the research conducted by Spitler et al.
(J. Econ. Entomol. 77: 1441-1444, 1984), both green and yellow Eureka
and Lisbon variety smooth-skinned lemons were used. In their discussion
of the results of the study, the researchers report: ``Although
maturity of the lemon (green or yellow) had no noticeable effect on the
number of flies collecting on the fruit, more punctures (707 green vs.
805 yellow per 10 fruit) and eggs (23 [green] vs. 46 [yellow]) per egg
cavity were found in the more mature yellow fruit. Even in a thin-
skinned lemon with 57 ovipositor wounds, no larvae or pupae (i.e., our
criterion of survival) were recovered.'' So, while the researchers did
observe that oviposition was more likely in the more mature yellow
fruit, they found that in only one case--in which the ripest fruit used
in the study was left in the infestation cage for 3 days in an attempt
to have egg survival--did any larvae or pupae survive (5 survivors out
of a very conservatively estimated population of 31,800). In the other
12 lots tested, in which the percentage of yellow lemons ranged from 50
to 100 percent in all lots but 1 (which was 100 percent green lemons),
there were no survivors out of a very conservatively estimated
population of 484,182. The results of this study, coupled with our
experience with both domestically produced and imported lemons, has led
us to conclude that the probability of a Medfly infestation resulting
from the importation of commercial shipments of smooth-skinned lemons
is extremely low. Thus, because we do not believe that it is necessary
to establish maximum maturity standards for smooth-skinned lemons
imported under this rule, we do not believe that it is necessary to
consider the impact of harvesting lemons at earlier stages on the
ability to detect any citrus black spot infection.
Comment: APHIS must consider the effects that fruit fly population
pressure and environmental stress on fruit trees may have on the
nonhost status of lemons. The existence of a large fruit fly population
in any given year or at any particular time of year substantially
increases the likelihood that the fruit flies will infest citrus fruit,
especially if other hosts are not available at that time, even if the
fruit is considered a poor host for fruit flies. Similarly, the effect
of plant stress on host resistance must be taken into account.
Therefore, APHIS should integrate on-site field inspections, trapping
programs, and/or possible field control programs for all species of
fruit flies into the systems approach for Argentine citrus, and should
require monitoring to ensure that no conditions arise that overwhelm
the lemons' resistance to fruit flies. Further, the effect of citrus
tree health on susceptibility should be included in the risk
assessment.
Response: In the research conducted by Spitler et al. discussed in
the previous comment, Eureka and Lisbon variety smooth-skinned lemons
were exposed to a high population pressure of 7,500 adult medflies per
3.6 m \3\ in the infestation cage, a population level unlikely to be
attained in the field. With that high population pressure in the
infestation cage, the researchers estimated that a total of 516,000
eggs were laid in the 13 lots of lemons used in the study, with only 5
pupae surviving, a mortality rate that exceeds the probit 9 security
level of 99.997 percent mortality (i.e., 1 survivor per 33,333). In the
last of the 13 lots tested, a total of 34 yellow lemons were placed in
the infestation cage for 1 day, after which the eggs in each lemon were
counted (rather than estimated). These 34 lemons yielded a total of
126,997 eggs, an average of 3,735 eggs per lemon. Despite this
exceedingly high per-fruit egg population, no larvae or pupae were
recovered from the lemons. The commenter further suggests that we
assess the effect of citrus tree health on host resistance. Official
records reflecting the host resistance of commercial smooth-skinned
lemons date back as far as 1914 (Quayle, H.J., ``Citrus fruit insects
in Mediterranean countries,'' USDA Bulletin 134, 1914), yet we have
been unable to find any records or other published material documenting
cases in which plant stress or other environmental conditions led to a
breakdown in that resistance.
Comment: Fruit flies in many cases prefer other hosts that are not
limited to subtropical or Mediterranean climates. For example, the
South American fruit fly and Medfly will lay eggs in stone fruit,
apples, or pears, which are grown commercially in many areas of the
United States. While it is unlikely that
[[Page 37629]]
the fruit flies would survive during the winter in northern regions of
the United States and become established permanently in these regions,
their introduction could still ruin local fruit crops for one season,
and fruit from temporarily infested regions could be transported into
more hospitable climates where the fruit flies could become
established. Therefore, APHIS' risk assessment should consider the full
range of environments in the risk assessment in which fruit flies, if
introduced, can cause significant damage to agricultural crops and
should develop confirming data on fruit fly distributions using insect
phenology models, such as those developed by plant protection
authorities in Australia (e.g., CLIMEX).
Response: The remote chance of the occurrence suggested by the
commenter is addressed in the risk assessment's node for ``pest finds
suitable host.'' We believe that it would be exceedingly unlikely that
fruit flies would be introduced in commercial shipments of Argentine
citrus fruit in such numbers that their populations would reach
outbreak levels in a matter of a few months. With regard to the use of
CLIMEX, we have found that this computerized climate matching system
can be overly conservative and often does not identify the full range
of areas into which we know a pest could spread. What we do in most
cases, and did do in the Argentine citrus risk assessment, is ask what
are all the locations that have both suitable hosts (not part of
CLIMEX) and suitable habitat (we consider additional factors not
considered by CLIMEX). Our results typically indicate that a pest could
spread to more areas than indicated by CLIMEX.
Comment: Having gone through two Medfly quarantines in the last 10
years because the USDA considers lemons a host to the Medfly, we find
it difficult to understand why Argentina is exempt from the same rules
that apply to our country. Similarly, California spends hundreds of
thousands of dollars per year on Medfly trapping, survey, and exclusion
activities, yet the proposed rule does not require any fruit fly
trapping in Argentina.
Response: Smooth-skinned lemons harvested for packing by commercial
packinghouses are not regulated articles under our domestic Medfly
regulations in Secs. 301.78-2, and it is those varieties of lemons that
are exempted from the cold treatment requirements of this rule. Thus,
there is no disparity between the provisions of this rule and our
domestic Medfly regulations in this regard. Any Medfly-related measures
that were applied to smooth-skinned lemons in California during Medfly
quarantines in that State were not due to APHIS regulations, but were
applied at the request of nations to which California growers sought to
export their product. The Medfly survey and exclusion activities
carried out by California are designed to maintain that State's freedom
from Medfly; similar requirements were not made part of this rule for
the export areas of northwestern Argentina because that region has not
been represented as a Medfly-free area.
Comment: Lemons have been stated to be nonhosts of fruit flies, but
during the Medfly eradication program in Ventura County, CA, and other
parts of California and in Hawaii, lemons have, in fact, been found
that were infested with Medfly larvae.
Response: Smooth-skinned lemons harvested for packing by commercial
packinghouses are not regulated articles under our domestic Medfly
regulations in Secs. 301.78-2, and this rule is consistent with our
domestic Medfly regulations. Neither the risk assessment nor proposed
rule stated that lemons in general were considered to be nonhosts of
fruit flies. Instead, both documents, as well as the supporting
research such as that conducted by Spitler et al. (1984), indicate that
it is only smooth-skinned varieties of lemons that are considered
nonhosts of fruit flies. Accordingly, this rule requires all lemons
other than smooth-skinned varieties to undergo specified cold
treatments to mitigate the risk presented by fruit flies, a
consideration reflected in the risk assessment. Considerable research
and investigations into anecdotal reports such as those cited by the
commenter have not uncovered any documented cases of Medfly attacking
smooth-skinned varieties of lemons.
Comment: No information appears to be available on what pesticides
are used or registered for use in Argentina. What assurances can the
USDA give that pesticide residues on imported fruit will not threaten
public health?
Response: The U.S. Food and Drug Administration (FDA) samples and
tests imported fruits and vegetables for pesticide residues. If residue
of a pesticide unapproved in the United States is found in a shipment
of imported fruit or vegetables, the shipment is denied entry into the
United States by the FDA.
Comment: APHIS has an obligation to the U.S. citrus grower
community to assess whether Argentine growers currently use pesticides
(for the control of pests or diseases) that cannot legally be used in
the United States. Further, APHIS should assess whether there would be
any substance that could be used in the United States to control a pest
or disease, should such a pest or disease be brought in that is not
currently present in the United States. If no substances are registered
in the United States that would replace those used in Argentina, APHIS
should not allow the citrus to be imported.
Response: As noted in the response to the previous comment, the FDA
samples and tests imported fruits and vegetables for pesticide
residues. The U.S. Government does not have any control over what
pesticides are approved for use in foreign countries. The Environmental
Protection Agency has regulations that address the exportation from the
United States of pesticides that are not registered for use in this
country and works with foreign environmental protection agencies and
agricultural producers to promote safer pesticide use and food
production practices. In response to the second part of the commenter's
remarks, there is a variety of fungicides and other pesticides
available for use in the United States in the unlikely event that a
plant pest is introduced into this country via citrus imported from
Argentina in accordance with this rule.
Comment: The proposed rule and risk assessment do not address the
legitimate concern that a pest that exists in one U.S. citrus-growing
region could be introduced by imported Argentine citrus into another
U.S. citrus-growing region that is free of that pest. For example,
brown citrus aphid (Toxoptera citricidus), a quarantine actionable pest
that is a vector of the tristeza virus, is listed as existing in
Florida in the 1997 Risk Assessment. Currently, Arizona and California,
which have limited occurrences of tristeza, have measures in place to
prevent the introduction of brown citrus aphid from Florida; Texas has
not had any serious tristeza outbreaks due to the lack of good vectors
for the virus. APHIS should address the possibility that pests
established in one part of the United States could be introduced into
free areas of this country via imported Argentine citrus. We suggest
that APHIS should require country-of-origin/lot number labeling of
individual fruit in order to address this concern and to allow for the
tracking of Argentine fruit if it becomes necessary. Further, APHIS
should develop an overall policy, consistent with WTO rules, for
dealing with this situation.
Response: The commenter raises the concern that pests established
in one part of the United States could be introduced into free areas of
this country via imported Argentine citrus,
[[Page 37630]]
and then suggests that country-of-origin/lot number labeling of
individual fruit to allow for the tracking of Argentine fruit could be
used to address that concern. To address the commenter's first concern,
in preparing our risk assessment, we identified all pests of citrus
known to be present in Argentina, examined the available information
regarding those pests, then focused our analysis on any pests that were
identified as quarantine actionable pests that could reasonably be
expected to follow the pathway, i.e., be included in commercial
shipments of citrus. With regard to the commenter's second concern,
this rule, in Sec. 319.56-2f(c)(6), requires that Argentine fruit be
packed in boxes that bear the SENASA registration number of the fruit's
grove of origin, so we will have the ability to track shipments of
imported Argentine fruit after they enter the United States. Although
the requirement was not added in response to this commenter's
suggestion, this final rule does, as explained earlier in this document
under the heading ``Specific Regulatory Changes Regarding Limited
Distribution,'' contain a requirement for the stickering of individual
Argentine fruit.
The commenter also urged APHIS to develop an overall policy,
consistent with WTO rules, for dealing with the issue of pests of
limited distribution. We believe that the new revised text of the IPPC,
which was approved by the FAO Conference at its 29th Session in
November 1997, provides the kind of overall policy sought by the
commenter. (The WTO SPS Agreement identifies the IPPC as the
organization providing international standards for measures implemented
by governments to protect their plant resources from harmful pests.)
Specifically, Article VI, ``Regulated pests,'' provides that:
``Contracting parties may require phytosanitary measures for quarantine
pests and regulated non-quarantine pests, provided that such measures
are: (a) no more stringent than measures applied to the same pests, if
present within the territory of the importing contracting party; and
(b) limited to what is necessary to protect plant health and/or
safeguard the intended use and can be technically justified by the
contracting party concerned.'' Under the Federal Plant Pest Act and the
Plant Quarantine Act, APHIS has the authority to take action against
pests of limited distribution in the United States when such pests are
found present in imported plants or plant products. Such action would
be in accord with WTO rules.
Comment: The risk assessment states that leprosis is found in
Florida, but an expert states that leprosis has been eradicated in
Florida since the early 1960's. Leprosis is not present in California
or Arizona. False spider mites (Brevipalpus spp.) are present in
Argentina and vector the virus for leprosis; these mites and their eggs
are difficult to detect through visual inspection, and the usual post-
harvest treatments have no effect on their presence. Although several
Brevipalpus spp. are present in the United States, the lack of leprosis
has made them less of a threat to U.S. agriculture. If the vectoring
mites and leprosis occur together in the northwest region of
Argentina--and there is evidence that leprosis is a serious disease in
Misiones Province in northern Argentina--then additional treatments of
all the fruit for the mites is required. APHIS should consider the risk
associated with Brevipalpus spp. remaining with the fruit through post-
harvest treatment and shipping and the risk of the mites carrying the
leprosis virus. If a risk is identified, then measures need to be taken
to prevent the mites from transmitting leprosis to the United States
via citrus, even if that disease exists in Florida.
Response: The expert mentioned by the commenter has not published
his findings regarding leprosis, whereas Alfieri, et al. (1994) and
Brunt, et al. (1996) both list leprosis as present in the United
States. As both leprosis and Brevipalpus spp. mites occur in the United
States and are not subject to official restrictions or regulations
(i.e., they are not listed as actionable and are not under an official
control program), these organisms do not meet the geographical and
regulatory definition of a quarantine pest.
Comment: The risk assessment does not account for the possibility
that a number of insect and mite species may be transmitted under the
calyx (button) of citrus fruits, thus allowing for the possibility of
transmission of such pests into the United States via Argentine citrus.
The calyx of citrus fruit can harbor a large number of insects and
mites or their eggs. These contaminant species are not easily visible
unless the button is removed (which leads to more rapid fruit decay)
and are resistant to cold treatment, surface washes, and insecticide
treatments. APHIS' risk assessment should address the issue of all
types of insect pests that may inhabit the calyx of Argentine citrus,
and calyx inspection should be a routine part of the inspection of
Argentine citrus at the port of first arrival.
Response: As indicated in an earlier response, in preparing our
risk assessment, we identified all pests of citrus known to be present
in Argentina, examined the available information regarding those pests,
then focused our analysis on any pests that were identified as
quarantine actionable pests that could reasonably be expected to follow
the pathway, i.e., be included in commercial shipments of citrus. In
examining the information regarding citrus pests present in Argentina,
we did not identify any insect or mite species that could be
transmitted under the calyx of citrus fruit that were quarantine
actionable pests that could reasonably be expected to follow the
pathway. Thus, we do not believe that it is necessary to include
provisions in this rule to require the routine calyx inspection at the
port of first arrival. However, this does not preclude our inspectors
from conducting calyx inspections, even on a routine basis, when they
believe such a measure might be necessary.
Disease Detection
Comment: The proposed rule states: ``If, during the course of any
inspection or testing required by this section or Sec. 319.56-6 of this
subpart, citrus black spot or sweet orange scab is detected on any
grapefruit, lemons, or oranges, the grove in which the fruit was grown
or is being grown shall be removed from the SENASA citrus export
program for the remainder of that year's growing and harvest season * *
*.'' It is currently unclear how much disease detection is needed to
cause SENASA to remove the grove from the export program. Does a single
infection on a single fruit disqualify an orchard from the export
program? The presence of the diseases can be detected in the litter and
occasionally the tree without obvious fruit infections. Would that be
grounds for the removal of a grove? A much clearer definition of when a
grove must be removed from the export program, and an explanation of
why that threshold for removal was chosen, needs to be established in
order to minimize the risk that latently infected fruit will reach the
United States. Further, the proposed rule contained no discussion of
whether any special criteria or measures need to be met for a grove to
re-enter the export program after it has been disqualified for a season
due to disease incidence.
Response: Paragraph (f) of Sec. 319.56-2f clearly states that if
citrus black spot or sweet orange scab is detected on any grapefruit,
lemons, or oranges, the grove will be removed from the export program.
So, in response to the
[[Page 37631]]
commenter's first question, a single infection on a single fruit, will
result in a grove's removal from the export program. That paragraph
does not, however, call for the removal of a grove from the export
program upon the detection of either disease in litter or in the tree
if the infection is not detected in the fruit, since there are no
requirements for the testing of litter or parts of the tree other than
the fruit. The commenter`s statement that the presence of citrus black
spot and sweet orange scab ``can be detected in the litter and
occasionally the tree without obvious fruit infections'' is true to a
certain extent; the fungi can be isolated from leaf litter and leaves
on the tree. However, the presence of these diseases cannot be reliably
detected through the visual inspection of plants or plant parts other
than the fruit. So, while Sec. 319.56-2f(b)(6)(i) does provide that a
grove's freedom from citrus black spot and sweet orange scab shall be
verified through visual inspection of the grove and buffer area, that
visual inspection will necessarily be limited to fruit on the trees.
The diseased fruit threshold was chosen because it will be the fruit
itself, and not any leaves, branches, or litter, that will be imported
into the United States. We did not include any special criteria or
measures for a previously disqualified grove to re-enter the export
program because we believe that the testing, treatment, and inspection
requirements that must be satisfied by any grove seeking to export
fruit to the United States make such additional measures unnecessary.
Comment: In the proposed rule, Sec. 319.56-2f(f) refers to
``growing,'' ``harvest,'' and ``shipping'' seasons, with no definition
of what is meant by such terms.
Response: We regard the ``growing season'' as the period between
bloom and fruit maturity, the ``harvest season'' as the period during
which the mature fruit are picked, and the ``shipping season'' as
beginning at roughly the same time as the harvest season and continuing
until shortly after the harvest ends. As we are using those terms in
their generally understood sense, we see no reason to specifically
define them in the regulations.
Comment: In Sec. 319.56-2f(f) of the proposed rule, it states that
fruit must pass ``any inspection or testing required by this section or
Sec. 319.56-6 of this subpart.'' Thus, if fruit is observed to be
infected before fungicide application, or at some random time (but not
during an inspection), or by non-SENASA personnel, there is strictly no
requirement to remove the grove from the export program, since these
inspections are not ``required.'' There is no overall catchall
requirement that any detection is sufficient to remove a grove from the
export program.
Response: We believe that the official inspections and tests called
for by this rule will be sufficient to detect the diseases of concern
should they be present in a grove or in harvested fruit. However, in
order to address the concerns raised by this commenter, we have added
the words ``or at any other time'' to Sec. 319.56-2f(f).
Comment: While the proposed rule specifies that any detection of
sweet orange scab or citrus black spot during required inspections
shall result in a grove's removal from the export program, it provides
no mechanism by which this shall happen. For example, there is no
requirement for SENASA to be notified, and no requirement for SENASA to
notify APHIS.
Response: In response to this comment, we have amended Sec. 319.56-
2f(f) in this final rule to require that both SENASA and APHIS be
notified in the event that citrus black spot or sweet orange scab is
detected.
Comment: While the proposed rule specifies that any detection of
sweet orange scab or citrus black spot during required inspections
shall result in a grove's removal from the export program, it does not
state what would occur if citrus canker was discovered in a grove or
within a particular growing region.
Response: As stated in the proposed rule, we believe that Argentina
has demonstrated, in accordance with FAO guidelines for pest-free
areas, that the citrus production areas in Catamarca, Jujuy, Salta, and
Tucuman are free from citrus canker. Should citrus canker be detected
in any of those States in the future, those same FAO guidelines require
that Argentina report that detection. Because the citrus fruit
regulations in Sec. 319.28 prohibit the importation of the fruits and
unprocessed peel of all species and varieties of the genus Citrus from
areas where citrus canker exists, the detection of citrus canker in an
area within the citrus-canker-free region of northwestern Argentina
would result in a prohibition on the importation into the United States
of grapefruit, lemons, and oranges from that area.
Comment: The proposed systems approach for citrus black spot and
sweet orange scab provides only suppression of symptoms and reduction
of the inoculum in the area proposed for export. So the question the
risk assessment must answer is will this provide the United States with
an appropriate level of protection against the introduction and
establishment of one or both of these diseases when it is clear that
infected, though symptomless, fruit will be certified for export to the
United States?
Response: The risk assessment provides the decisionmaker with the
information he needs to determine whether certain phytosanitary
measures provide ``an appropriate level of protection'' in a particular
situation; it is not the purpose of the risk assessment itself to
answer that question. In this case, the risk assessment examined the
risk associated with the importation of Argentine citrus and estimated
the likelihood of pest introduction. In any event, the systems approach
for citrus black spot and sweet orange scab is not designed to suppress
symptoms. It is designed to prevent infection. For that reason, part of
the systems approach includes removal of debris to reduce inoculum and
application of fungicides to prevent infection. As part of the entire
systems approach, this prevention portion provides an appropriate level
of protection against the introduction or establishment of either of
these diseases. It is not ``clear'' that symptomless, infected fruit
will be certified for export. In fact, using the systems approach makes
it highly unlikely that symptomless, infected fruit will be certified
for export.
Risk Assessment
Note: In this section, as well as in the subsequent section
titled ``Risk Assessment--`Principles of Good Practice' some of the
comments state that the proposed rule's supporting risk assessment
failed to establish a connection between certain of its conclusions
and the data or information that was used as the basis for those
conclusions. We have responded to those comments by explaining the
role that expert judgment played in reaching those conclusions or by
pointing to our use of the sources cited in section III
(``References'') of the risk assessment. However, in order to more
thoroughly document the sources of the risk assessment's
conclusions, we have prepared an addendum to the risk assessment
that provides, node-by-node, specific references to the information
or data used as the basis for those conclusions. The addendum may be
obtained from the person listed at the beginning of this final rule
under the heading FOR FURTHER INFORMATION CONTACT.
Comment: The consequences of introduction are addressed in the
qualitative portion of the risk assessment via an estimation of the
economic and/or environmental damage potential according to ratings
applied to five risk elements. In these estimations, broad
uncharacterized assumptions are used and the role of uncertainty is
never discussed.