Viruses
First Rays Orchids
orchids, and the other individual commented that friends in her orchid
society had recently been devastated by large-scale losses in their
collections due to viruses, and they were in search of only virus-free
stock.
It is my firm belief that orchids, like people (and all living creatures,
for that matter), harbor all kinds of pathogens - essentially anything and
everything to which they have ever been exposed - but may not display any
symptoms nor be affected by them. It is very likely that such plants, if
well-grown, may never exhibit problems. I have read that pretty much all
phalaenopsis carry viruses, and if that is true, there sure are a lot of
growers who verify that last statement.
What kinds of evidence and opinions do we have on this subject?
--
Ray Barkalow --<>-- First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info
"I'm not getting old. I just need repotting"
TQPL
Thanks for bringing up an important plant health issue.
I personally think the subject of plant virus infection is greatly
understated in much of horticulture and from a scientific standpoint the
only way to truely determine if a plant has a virus infection is to have it
virus indexed, be this by indicator plant, electron microscopy, or
serologically. All of the above assay methods can also be subject problems
and false positive and false negative results. Immunological or serological
assay is specific for a specific virus or virus group and does not
necessarily mean the plants are free of other virus infections - pathogenic
of otherwise.
Thorough assay (for something like commercially important Surfinia Petunia)
might involve upto 20 different virus index assays. Nobody does that many
for orchids!
Assay only give a snapshot in time and there is no guarantee that plants
have not become infected subsequently. Indeed this would be a practical
consideration for anyone in search of 'virus-free' stock.
This is one of the reasons why tissue culture labs that are involved in
virus index stock invest in aphid screeing.
It is also certainly true that good cultural conditions can mask virus
expression and the plants appear to be virus free though they are infact
asymptomatic at that cultural point in time. Put the plant under stress and
symptoms will probably appear although this might be affected by growth
cycle. The danger point is such plants are infective all all points in time
by artifical or natural vector tranmission.
Having worked in the commercial orchid industry (with aphid screened houses)
there is ample evidence of the problem out there if it is looked for. We
used to regularly burn a lot of plants, compost and pots as a strict
elimination program. My apparent paranoia about the problem also is a result
of having spent 13 years in a University plant pathogen department working
with plant virus infections. There with all the facilities necessary for
detection, all vegetatively propagated plants were looked at with suspicion
and we could readily find infection in them even though many appeared
asymptomatic.
Most people do not like to hear or imagine there is a problem with virus
infection in orchids, especially their own plants, but it is better to be
aware of the facts, and then precautions to prevent infection of your other
plants can be achieved, and your plants will grow better.
It is better to be cautious than have to burn all you plants later.
Best regards
Alan L Winthrop.
TQP...@awinthrop.freeserve.co.uk
"First Rays Orchids" <ray...@firstrays.com> wrote in message
news:8tblgu$n06$1...@slb3.atl.mindspring.net...
> I friends in her orchid
> society had recently been devastated by large-scale losses in their
> collections due to viruses, and they were in search of only virus-free
> stock.
>
Al
jumping of point to read more about this subject:
http://pages.prodigy.net/geotan1/viruslinks.htm
A long time ago I read that orchids collected from the wild were virtually
virus free but that those in most collections were viruses. The conclusion
that was drawn was that humans were the main vectors in the captive orchid
collection. Is this true?
It seems to me that if so many orchids are infected that most of us have
some pretty healthy looking virused plants.
Given your point of view on this subject, TQPL, what is the average hobbyist
to do? What precautions should be taken?
How can we adjust our behavior around the plants to help prevent the spread
of these viruses? If we wipe the leaves to clean them, are we spreading
virus as we move from plant to plant?
Besides putting insect screening on the doors and inlet shutters of the
growrooms/greenhouses and sterilizing our cutting tools and potting
accoutrements, what else can we do in the general environment to prevent the
spread of virus?
Do chemicals like RD-20 and Physan, that are advertised to "kill" virus,
help in any way?
I may have more questions later. :-)
"TQPL" <TQP...@awinthrop.freeserve.co.uk> wrote in message
news:8tc0fh$4v1$1...@news8.svr.pol.co.uk...
K Barrett
Perhaps I'll arrange a topic evening on it and invite you to join with
your questions.
Most recently:
**************
MarilyninOttawa
Probably the most awkward questions I receive have to do with virus. 'Is
my plant virused?' (We can arrange for a test) If the plant is proven to
be virused, how can we easily tell the owner about the implications of
the disease and the ultimate and likely fate of that plant? It is not an
easy task. Any suggestions??
Ed_in_SAT
Teach people to screen with indicator plants. Chenopodium ameranthicolor
comes to mind. Quick, cheap, plants are weeds that grow almost anywhere.
MarilyninOttawa
I agree that we can teach people how to test, the challenge lies with
telling them that there is no cure.
Zeynep
Ed, can you elaborate, please?
Jade
Ed, can other Chenapodium species be used. I have plenty of Chenapodium
album but haven't seen any of the others.
Ed_in_SAT
Hi, Zey. Elaborate on indicator plants? Not much to say. A few plants
react specifically when infected with virus. A very few of these are
leaf specific so you can use each leaf to make a different test. You
express some "juice" from a suspect plant leaf or stem, put it on a few
grains
of sand and scrub it across the leaf of an indicator plant. In a few
days, a reaction will appear if certain viruses are present. Chenopodium
ameranthicolor happens to be a widely available plant for this.
Ed_in_SAT
Jade. sorry, I do not have specific information on 'album' as an
indicator.
*************
I'm pretty sure Aaron has info in his FAQ (well, no, he doesn't, but I'm
posting the link anyway cause its got some other good stuff in there...
http://www.nmt.edu/ftp/orchids/) and I also have this link.
http://biology.anu.edu.au/Groups/MES/vide/famly094.htm
I think many of teh older catts which were used primarily in teh cut
flower trade can be assumed to be virused, because of all the cutting
they went through. (Non sterile blades). But unless the pathogen shows
itself in teh flower or body, then I am with you. Plants are full of
viruses which may not 'show'. Come to think of it again, the OLD had
tons on info on viruses so I'll post that link too.
http://psppathsrv.unl.edu/orchid/orchid.htm
K Barrett
K Barrett
bad that it is gone...
Do a custom search after selecting the OLD database
enter the word 'virus' in the slot for 'abstracts'
Read the stuff from Bob Hamilton, Paphnut (who was a weirdo but had good
info) Rob Halgren, and (sheesh) a ton of other people.
K Barrett
WNeptune
From: "First Rays Orchids" ray...@firstrays.com
Date: Fri, Oct 27, 2000 10:31 AM
Message-id: <8tblgu$n06$1...@slb3.atl.mindspring.net>
I was recently in a discussion concerning the prevalence of viruses in
orchids, and the other individual commented that friends in her orchid
society had recently been devastated by large-scale losses in their
collections due to viruses, and they were in search of only virus-free
stock.
It is my firm belief that orchids, like people (and all living creatures,
for that matter), harbor all kinds of pathogens - essentially anything and
everything to which they have ever been exposed - but may not display any
symptoms nor be affected by them. It is very likely that such plants, if
well-grown, may never exhibit problems. I have read that pretty much all
phalaenopsis carry viruses, and if that is true, there sure are a lot of
growers who verify that last statement.
What kinds of evidence and opinions do we have on this subject?
-->>
This is a real can of worms. I can hear the screaming and gnashing of teeth,
already. Having been a reasonably successful, amateur grower for more than 25
years, I believe I am entitled to voice my opinion.
Aseptic technic
I am somewhat reluctant to tell that I do not attempt to practice aseptic
technic in dividing plants, although with my professional background I believe
I am as familiar with the technic as anyone. As an undergraduate I majored in
bacteriology; and as a physician I practiced thoracic and cardiovascular
surgery where aseptic technic was absolutely essential.
The first five years of growing orchids I did all of the maneuvers advised by
many, using a clean razor blade to cut all plant tissue, or instruments which
had been sterilized by flame. After reading reviews by several experts in the
field of plant virology, and observing the lack of any semblance of sterile
technic by many successful growers, I came to the conclussion that to carry out
proper sterility the following would have to be done: All cutting instruments
should be flame sterilized between plants; no dipping of plants in a common
bucket of fertilizer, no dipping of potted plants in a common bucket for insect
control; one would need to scrub their hands between handling all plant
material; all new plants would need isolation for at least three months, and
then checked for virus prior to going into the collection; no two plants could
touch each other; overhead plants could not be watered, if water were to drip
on any plants below; mounted plants could not be hung up on walls and watered
as water would splash on to other plants; plants could not spend any time
outside as they would be cross contaminated by wind, rain, and insects; all
pots, tags, hangers, and stakes would need to be sterilized before reused; and
insect control would need to be 100% effective. Literally, each individual
plant would need its own specific wardian chamber to remain disease free.
Does that mean I have never had virus in my collection? Of course not. On the
rare occassion of seeing color break in flowers, and assuming this was virus, I
have discarded the plant. On the rare occassion I have seen what I thought was
most likely virus, but without any problem with growth, or flowering, I have
merely continued to grow it as previously, and enjoy the flowers.
I have a fairly large collection, often in excess of 1000 plants, some of which
I have been growing for more than 25 years. While I do not even suggest the
collection is free of virus, I am not aware of a problem in growth or flower
production. I personally doubt any collection of any size or age is free of
virus, especially if it contains many Cattleys, or Cymbidiums.
Wilford Neptune
Paul M
some known research done at the University of Hawaii and U of Florida.
Many attempts at finding virus on orchids in the wild has never been found.
There were a few reports but they were not substantiated.
It has been then assumed that most virus has been man made so to speak.
That old thing about smoking in the greenhouse has been found to have merit
as transmission of Tobacco mosaic has been done to orchids, especially
Cymbidium.
So the occurance of virus is likely. The main ways of infection are by using
infected tools, touching the plant that have been wounded and insect
transmission.
One has to remember that there is a critical virus load (concentration) of
virus particles to infect a plant. Many times this does not easily occur
however with repeated attacks by insects and using unclean tools between
grooming plants you increase the chances of infecting healthy plants.
Work done shows that the known orchid virus are very unlikely to transmit by
seed. So your breeding efforts of using a virus plant should be safe. I
say should be since the study of the orchid see virus transmission did have
some unproven infection (data could not substantiate presence). The
chances are still very slim.
The very best sterilization is the use of flame. You must however remove
all debris from blades before flaming tools. A good wipe of the tool then
flame between plants is a good method. The use of chemicals such as bleach,
RD-20, Physan are effective, however the key is the concentration, freshness
and time of soaking. It is recommened that clean solutions be made up daily
and that if you have a lot of plants, change the solution about every 10
plants or so. The duration is another thing. Bleach is very good at the
10-20% concentration but you need at least 5-10 minutes of soaking to render
a good clean tool. The RD-20 and Physan take a lot more soaking time, one
study said that 20 minutes are needed to be clean. One thing to note is
that all these chemicals play havoc with your tools as oxidation and
destruction of the metal plating occurs.
Alcohol at 75% is also effective with prolonged soaking of 5 minutes, better
yet, dip in Alcohol and then flame the tools. Gut many "blue" fires occur
by ignition of the alcohol so this is not all that safe.
The can of worms as one commented is in Tissue Culturing. Unfortunately not
all orchid clones that have been Tissue cultured are really virus free. I
have already seen many clones with suspect symptoms and upon futher testing,
in fact they were infected. Again, its sometimes the blame of the tissue
culturing facility. The mother plant was clean, however, the tools at the
lab were not fully sterilized and transmission occurred.
Plants of this nature are not "dangerous" providing your aware of the nature
of the plant and do a good culture management job. Keep the plants in
special places so that insects do not travel between them and the clean
ones. Also take extra precautions to really clean your tools and hands when
you work on them. I can think of several plants that were accidentally
cloned without knowledge of virus presence and these were used later in
breeding.
Virus detection unfortunately is expensive, but the use of your own "spot"
testing with Chenopodium or Amaranth is one way as someone pointed out a way
to check for presence. It takes practice to get the abrasive wipe technique
to work.
I would say for the most part, if the plant is not going downhill and that
you are very careful about culture management you can safely keep plants
that are known or suspected to have virus in your collection. You can enjoy
them until such time, they may decline or really show virus symptoms. You
just have to take those extra precautions.
It is unfortunate, but I have seen some new mericlones which have not even
reached blooming stage, which showed virus symptoms. These plants from a
reputable lab were supposed to be free, but somehow they got infected. So
be aware that it is very possible to get infected plants without your
knowledge.
"First Rays Orchids" <ray...@firstrays.com> wrote in message
news:8tblgu$n06$1...@slb3.atl.mindspring.net...
TQPL
I have to agree with a lot of the points you make about human vectors and
healthy looking plants that are possibly infected.
As for wiping leaves... I believe it depends on how likely there is to be
sap tranmission.
With non-orchidaceous plants such as tomato simply brushing the infected
tomato leaf hairs can be enough. With that in mind, perhaps every time you
clean a different
plant use a different pad and spray the cleaner onto each plants prior to
cleaning.
General environmental awareness helps with regard plant virus. Many other
non orchid plants can harbour virus, be especially vigilent about know
carriers. Many lillies, tobacco, and common weeds can be a source. If
plants are grown outdoors be aware of possible transmission from leaf
sucking pests. Watch out for thrips, aphids and Bemesia white fly all of
which are known vectors. Keep your cutting tools for orchids separate and
sterilized.
When repotting be aware of risks in re-using materials such as pots and
canes. Bleach should stop the problem if you have to re-use. Do not recycle
potting materials.
Products such as Physan and Virkon-S are anti-virucidal, but work in Holland
has revealed that the latter might not stop transmission if simply use as a
blade dip prior to plant cutting.
Smoking in the greenhouse is a definative no no...while handling plants
after smoking is a very bad idea.
Buying plants from trusted orchid nurseries is obviously a _very_ good
policy. Having heard what goes on in some nurseries in Holland I personally
would be wary about those outlets that cater for the pot plant industry as I
am sure some of the plant health controls are suspect worldwide.
Some genera are less likely to become infected, and Paphiopedilums generally
are not troubled by virus infection though recent findings have revealed
that they are not beyond becoming infected.
Any questions ... ask away.
Hope this helps.
Best regards
Alan.
TQP...@awinthrop.freeserve.co.uk
"Al" <A...@orchidexchange.com> wrote in message
news:8tc2h8$omn$1...@bob.news.rcn.net...
C. Early
The short answer:
This issue involves, to greater or lesser degrees, depending on one's
tendencies, the following: 1) science, 2) myth and hearsay, 3) paranoia, 4)
the size of one's bankroll.
It all boils down to the fact that, "There ain't no perfect answer." You
can test by various methods for a limited number of viruses known to infect
orchids. You also can take, as Dr. Neptune has concisely delineated below
(and I've shamelessly pasted in), some fairly simple, inexpensive measures
to limit the potential for spread of pathogens, known and unknown, from
plant to plant. All you plant-in-the-bucket-to-save-fertilizer dunkers
should just go ahead and start the bonfire now.
From Dr. Neptune:
"All cutting instruments
should be flame sterilized between plants; no dipping of plants in a common
bucket of fertilizer, no dipping of potted plants in a common bucket for
insect
control; one would need to scrub their hands between handling all plant
material; all new plants would need isolation for at least three months, and
then checked for virus prior to going into the collection; no two plants
could
touch each other; overhead plants could not be watered, if water were to
drip
on any plants below; mounted plants could not be hung up on walls and
watered
as water would splash on to other plants; plants could not spend any time
outside as they would be cross contaminated by wind, rain, and insects; all
pots, tags, hangers, and stakes would need to be sterilized before reused;
and
insect control would need to be 100% effective."
This is why it's such a great hobby - we never run out of things to worry
about or spend money on!
Cal Early
pha...@my-deja.com
but not necessarily advocated by Wilford) I would quit growing orchids.
I could maybe keep a half dozen plants instead of the over 200 that I
have and it wouldn't be fun anymore.
In article <8tcldu$tj$1...@news1.kornet.net>,
Sent via Deja.com http://www.deja.com/
Before you buy.
Wendy
I have a Catt. just opening & the sepals are blotchy!! Does this mean it's a
virus??
What else could cause this?
Cheers Wendy
"First Rays Orchids" <ray...@firstrays.com> wrote in message
news:8tblgu$n06$1...@slb3.atl.mindspring.net...
Ken Woodward
What you say makes sense to me. Perhaps we make too much of the viruses
that probably are lurking in most of our orchids. Maybe we would better off
to worry more about achieving the best possible growing conditions and not
get paranoid about viruses that don't have any visible effect on the plant.
Al seems to think that it is the human vector that spreads the viruses.
That certainly may be true of some. Tobacco mosaic virus may well be spread
by smokers. I remember that the insecticide of choice before DDT was
nicotine soleplate. Some of the chemists here could give an opinion about
whether viruses could have been spread through use of that insecticide. If
aphids are a vector for the spread of viruses, how could plants from the
wild be virus free?
We could take steps to eliminate the viruses by destroying all our orchids.
We could eliminate childhood diseases by destroying all our children. It
seems more humane to nurture them.
_________________
__ Ken Woodward ___
____Newton, MA___
"First Rays Orchids" <ray...@firstrays.com> wrote in message
news:8tblgu$n06$1...@slb3.atl.mindspring.net...
Eric Muehlbauer
square-shaped pattern. Not bad enough to ruin the flower, which was
gorgeous, but enough to convince me that it was virused. I isolated the
plant and checked the opinions of my list-mates (ODO). I was ready to
just chuck the plant...Rod and other list members convinced me to have
the plant tested, not just for my info but for the original grower as
well. When I did, it came back completely negative for several viruses.
In revenge, the plant hasn't bloomed since....Take care, Eric Muehlbauer
C. Early
"nicotine soleplate"???!!!
I truly am not trying to be mean - this misspelling gave me a good guffaw.
It should have been "sulfate" or "sulphate", depending on which side of the
Atlantic one is on.
One of the best misspellings I've ever seen was on a patient's medical
history where he had listed "hot riders" as one of his existing
diseases/health problems. Anyone want to take a guess what it was? (hint: a
very common condition among most of us perhaps)
Ken Woodward
nicotine sulfate.
"Ken Woodward" <kenwo...@mediaone.net> wrote in message
news:uZoK5.8641$_17.1...@typhoon.ne.mediaone.net...
John G. Talpa
John G. Talpa, CWS-VI
Certified Water Specialist
JT Company
"C. Early" <ear...@kornet.net> wrote in message
news:8tdei5$qmk$1...@news2.kornet.net...
TQPL
As you rightly pointed out there is a difference in the types of nicotine
used as insecticides.
In the distant past when it was permitted - the cans of commercial nicotine
shreds specifically stated they were 'manufactured synthetically' and therby
avoided any risk from TMV..... so there is a significant difference.
Best regards,
Alan
TQP...@awinthrop.freeserve.co.uk
"Ken Woodward"
I remember that the insecticide of choice before DDT was
> > nicotine sulplate. Some of the chemists here could give an opinion
> about
> > whether viruses could have been spread through use of that insecticide.
Victor Gibson
Scott
Wendy
I wonder if systemic insect poisons could make the petals blotchy??
"Eric Muehlbauer" <e.mueh...@worldnet.att.net> wrote in message
news:39FA30FB...@worldnet.att.net...
HMSDOC
>seems more humane to nurture them.
Guess you have never had to deal with my kids! LOL
Relax, only kidding..
Howard
First Rays Orchids
and ended up with light/dark, blotchy leaves. They eventually smoothed out
and returned to an even green color.
--
Ray Barkalow --<>-- First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info
"I'm not getting old. I just need repotting"
"Wendy" <wen...@home.com> wrote in message
news:VEBK5.211151$3E6.2...@news1.alsv1.occa.home.com...
C. Early
RJ Lopez
deal with viruses all the time and manage to prosper and reproduce.
Why are people so worried about this if it can be likened to people
getting colds, herpes simplex, etc. ? Don't plants have decent inmune
systems like animals do?
RJ
>
>Does that mean I have never had virus in my collection? Of course not. On the
>rare occassion of seeing color break in flowers, and assuming this was virus, I
>have discarded the plant. On the rare occassion I have seen what I thought was
>most likely virus, but without any problem with growth, or flowering, I have
>merely continued to grow it as previously, and enjoy the flowers.
RJ Lopez
Raleigh, NC
Delete NONCSPAM from address to reply via email.
Karen
a newby, I've learned quite a bit today.
Thanks!
Karen
Steve
<benderla...@hotmail.com> writes:
>You would expect that orchids in the wild
>deal with viruses all the time and manage to prosper and reproduce.
Orchids in the wild seem to rarely have viruses.
>Why are people so worried about this if it can be likened to people
>getting colds, herpes simplex, etc. ? Don't plants have decent inmune
>systems like animals do?
No, actually they don't.
to reply, delete xspam.
Steve
in the Adirondacks of northern NY
RJ Lopez
can read up on virii in plants? It's a fascinating subject and so far
I haven't seen a comprehensive discussion of the pathology of orchid
genera, just expositions on hygiene. Thanks, RJ
>>Why are people so worried about this if it can be likened to people
>>getting colds, herpes simplex, etc. ? Don't plants have decent inmune
>>systems like animals do?
>
>No, actually they don't.
>
RJ Lopez
TQPL
The subject of suscecptibility of virus infection and plant 'immunity' is a
interesting one...
You are certainly right that plants do not have an immune response like us -
but
things are always complicated in life!
A resistance to infection from plant virus strains can be achieved in
Tomato, by innoculating with a mild strain of TMV and this confers
resistance to the more damaging infections for the plant later in life.
Ideed it it quite a common commercial practice.
Also plants can produce a phytoalexine responses to infection, for example
when challenged by fungi, some plants will thicken possible entry points to
the infection such as the stomata and seal off the site of damage. Trying to
infect the plants later by the same pathogen the plant resists better and
new stomatal entry is stopped on other leaves.
Many common deciduous temperate trees eg. Oak, respond to insect attact by
activating a chemical response to make subsequent 'grazing' less tasty.
Regards
Alan
TQP...@awinthrop.freeserve.co.uk
"Steve" <>
.
>
? Don't plants have decent inmune
> >systems like animals do?
>
> No, actually they don't.
>
Leanne Forsyth
> This interesting subject has lots of implications. Let me just comment on
> some known research done at the University of Hawaii and U of Florida.
> Many attempts at finding virus on orchids in the wild has never been found.
> There were a few reports but they were not substantiated.
The university of Queensland did a huge huge survey of australian orchids
in the wild and found that TMV and ringspot (the poty virus) were
prevalent everywhere... even in sites previously never seen before by man
(yes even in a slightly civilised/populated country like Australia there
are large sections where no one has ever been before and this research
group had a lot of fun getting there...) some of the conclusions that I
drew from their results were that most people who had *any* wild collected
Australian native orchid was likely to have some viruses in their
collection, and as the poty virus (that I can't remember the name of..) is
transmitted by false spider mites (the little buggers that invade pretty
much every summer) a lot of their orchids were likely to be
virused.... depressing as it is viruses are present in just about every
collection but not always a problem as long as due care is taken.... just
a little point flaming of instruments is able to sterilise from fungal and
bacterial pathogens BUT DOES NOTHING TO VIRUSES soaking in a strong basic
solution (trisodium phosphate ph 14) is required to break the bonds in the
virus....
TQPL
That's is some important info you have posted. Do you know if the University
of Queensland published their findings and where I might be able to refer to
it? (Is that St Lucia, Bribane where the Jacarandas must now be blooming)?
Poty virus infections are very prevalent in many tropical plants and Sweet
Potatoe has a problem with it. Infact a good idicator plant for it is the
other Convolvulaceae member
Ipomoea 'Hevenly Blue' - that's what the guys from CIP in Peru use. It will
kill a seedling very quickly.... not a nice sight! I've had hundreds of
plants die that way.
I must admit I have always wondered about the wild collected plants being
'free from virus theology'. The thought of a jungle collector cutting plants
with the same machete and subdividing them always had me theoretically
worried about virus transmission.
Thanks for your great info.
Best regards
Alan
TQP...@awinthrop.freeserve.co.uk
"Leanne Forsyth" <:
>
> The university of Queensland did a huge huge survey of australian orchids
> in the wild and found that TMV and ringspot (the poty virus) were
> prevalent everywhere... even in sites previously never seen before by man