Orchid disease - Fungus ?

[hoki...@gmail.com]

Dear Doctor,

I bought a Miltonia and a Zygopetalum at the San Francisco Orchid
Society Exposition earlier this month. I discovered that they both
have black spots and I suspect that this due to a fungus.
I took some pictures of one ‘infected’ leaf and uploaded them here:
http://picasaweb.google.com/hokidachi/Orchids#
Could you please have a look at those pictures and let me know what
you think?

Thank you very much for your help.

Hokidachi

[dennis...@aol.com]

Dear Hokidachi:

You do in fact have an active infection on your Zygopetalum leaf. I
wish you had also posted a picture of the Miltonia because not all
infections are found on different genera. Please remove the infected
leaf on the Zygo as soon as possible (because it is oozing liquid, and
thus very active), and spray with the entire plant with Physan.

But also get back to me with a description of how and where you are
growing these plants. A name on the Zygo would also be of interest as
they are not all cold growers.

Sincerely,
Dennis

[hoki...@gmail.com]

Dear Doctor,

Thank you for your help. I cut the infected leaves and order Physan on
Internet (I should have it by the end of the week).
I took additional pictures including the Miltonia, you can see them
here http://picasaweb.google.com/hokidachi/Orchids#
Unfortunately I can't tell you the exact name of the zygo as it did
not have any description, maybe the photo will help. The Miltonia
description is just "easter miltonia".
I have the following orchids: a Miltonia, a Cynbidium, a Masdevallia,
a Dendrobium, Epidendrums (radican & polybulbon) and several
Phalaenopsis.
They all are in my living room close to a south-west facing window.
They each receive their own fertilizer, usually every two weeks or
less depending on the season.
Please let me know if you need more information.

Regards,

Hokidachi

[dennis...@aol.com]

Dear Hokidachi:

You should treat the miltonia the same way as the Zygopetalum. Remove
infected tissue, well into healthy leaf area with a clean, sharp
blade. Treat the plant with the Physan.

The problem may well be that the conditions under which you are
growing these orchids are only appropriate for some of them. If your
Phalaenopsis have been happy than the conditions are too warm and not
bright enough for the Zygopetalum, Miltonia, Cymbidium, and
Masdevallia. It is also likely not bright enough for the Dendrobium
and Epis (I cannot comment on the temperature needs of the Dendrobium
without knowing what kind it is, they are very varied).

There also may not be strong enough air circulation for them.
Cymbidiums, Masdevallias (most Masdevallias at least), and
Zygopetalums are usually grown outdoors in the Bay Area because they
need cool to cold nights and strong air movement to stay healthy. They
also need really good light, especially the Cym. and Zygo. Miltonias
(the big flowered ones are actually Miltoniopsis) need cooler
temperatures than a Phalaenopsis, and better air movement. The bottom
line is that not all orchids can be grown together.

Conditions that are stressful (especially poor light, low air
movement, and improper night temperature) predispose plants to fungal
or bacterial infection. Please check the downloadable culture sheets
we have on the Orchid Doctor Page at www.orchidsanfrancisco.org. It
will give you the info you need to properly locate the plants.

Sincerely,
Dennis

[hoki...@gmail.com]

Dear Doctor,

Thank you very much for the analysis and comments.

I removed the infected tissues (and sometimes entire leaves) and
treated all my orchids with Physan.
I really hope that I did everything properly and that my orchids will
survive.

I also placed the dendrobium, cymbidium, epidendrum (radican) and
zygopetalum outside. There are on a bench under a tree with sun in the
morning until 11AM, partial shade until 4PM and then sun again until
the night. While those conditions may not be optimum for all of them,
I suppose they are much better than before (i.e. in my living room).
While I was checking the light and temperature needed for each
orchids, I discovered that both the masdevalia and miltoniopsis need a
minimum temperature in the 50S. In my garden I have at night 45F and
sometimes lower. Is that still ok to place them outside?

For your information, I checked the culture sheets on the Orchid
Doctor page at http://www.orchidsanfrancisco.org. All the links are
actually broken, it seems that the American Orchid Society changed the
sheets location on their website. As an example the link for
Dendrobiums is http://aos.org/aos/uploadedfiles/docs/culturedendrobe.pdf
while it should be
http://www.aos.org/Content/ContentFolders2/ContentType/Articles/CultureSheets/ByGenre/cultureintermeddendrobe.pdf

I sincerely thank you for your time and help.

Regards,

Hokidachi

[dennis...@aol.com]

Dear Hokidachi:

As I do not know which particular Dendrobium you have I do not
recommend putting it outside, as some species will be quickly damaged
by our low night temperatures. Others will want our cold nights. My
comment on the light was based on my feeling that "near" a south-west
window did not mean IN the southeast window.

There are some Masdevallias that will not tolerate the occasional
night down to 45, and many that love it, or need it to bloom, so I
would want to know the name of the Masdevallia to comment.
Miltoniopsis really do not want to be subjected to temperatures below
50, so I would look for a cool very bright place in the house to grow
it, and try to provide the best air circulation you can to reduce the
possibility of fungus. Remember, that orchids really need to be in
windows; and being near windows (like 4 or 5 feet away), especially
being placed to one side of a window, is often barely any light at
all, even if the window is bright.

Sincerely,
Dennis

On Apr 5, 6:49�pm, "hokida...@gmail.com" <hokida...@gmail.com> wrote:
> Dear Doctor,
>
> Thank you very much for the analysis and comments.
>
> I removed the infected tissues (and sometimes entire leaves) and
> treated all my orchids with Physan.
> I really hope that I did everything properly and that my orchids will
> survive.
>
> I also placed the dendrobium, cymbidium, epidendrum (radican) and
> zygopetalum outside. There are on a bench under a tree with sun in the
> morning until 11AM, partial shade until 4PM and then sun again until
> the night. While those conditions may not be optimum for all of them,
> I suppose they are much better than before (i.e. in my living room).
> While I was checking the light and temperature needed for each
> orchids, I discovered that both the masdevalia and miltoniopsis need a
> minimum temperature in the 50S. In my garden I have at night 45F and
> sometimes lower. Is that still ok to place them outside?
>
> For your information, I checked the culture sheets on the Orchid

> Doctor page athttp://www.orchidsanfrancisco.org. All the links are

> actually broken, it seems that the American Orchid Society changed the
> sheets location on their website. As an example the link for
> Dendrobiums ishttp://aos.org/aos/uploadedfiles/docs/culturedendrobe.pdf

> while it should behttp://www.aos.org/Content/ContentFolders2/ContentType/Articles/Cultu...

[hoki...@gmail.com]

Dear Doctor,

I again thank you a lot. I really appreciate your help.

My Dendrobium is a Nobile (Starclass) and the Masdevallia is a Golden
Monarch.

I would love to place my orchids in windows but my house is not
designed accordingly. I managed to get the Laelia (Cinnabarina) and
the Dendrobium to bloom.
Unfortunately, I now know that it'll be almost impossible to have some
other genera to bloom under the same conditions (like oncidiums).

Regards,

Hokidachi

[dennis...@aol.com]

Dear Hokidachi:

You should be able to grow and bloom Nobile type Dendrobiums outdoors.
They will need overhead cover to keep them dry in the winter, and to
be brought inside if the temperature is going to fall below 40. You'll
also need to protect them from snails and slugs as they really love
them.

Masd. Golden Monarch should also be able to grow outdoors with some
attention to it not being too wet in the winter (and similar attention
to excessive cold below 45 or so). I find that repotting in the early
fall helps when growing Masdevallias outdoors. It assures that they
have the best possible drainage through the rainy season.

As a final note, I believe that if you can bloom Laelia cinnabarina,
there are Oncidiums you can grow and bloom.

Dennis

[hoki...@gmail.com]

Dear Doctor,

Thank you for your great help!

Best regards,

Hokidachi