Sick Phalenopsis

[Lily]

Hello, I have not received anything for a while so I hope that you are
still taking questions about Orchids. I have an Orchid that has
started to go downhill. I keep my Phalenopsis in a room where they
get morning light and it is fairly bright but no direct sun. I
uploaded a picture of this Orchid to the Gallery under my name
"Lily". I have had this plant for a couple of years and last year it
bloomed and has always looked very healthy. I noticed that there were
bumps on the leaf and I thought that it might be edema from
overwatering so I decided to let it dry out more. One leaf, as you
can see, turned brown and looks really bad. The other leaf looks
pretty much like it will go, also. I would really like to know what
happened so that I can keep my other phalenopsis from getting sick
although I noticed a leaf getting bumpy on one of the other ones. Is
there a treatment? I have isolated the sick ones but they may have
already infected the others. Thank you so much for taking questions
and helping. Lily

[orchid doctor]

Hi Lily:

I am still taking questions. Activitiy has just been slow of late. The
appearance of the bumpy leaf is indicative of attack by false spider
mites. these are tiny pests that are just barely visible with a
magnifying glass. they rasp the leaf surface and can cause this kind
of appearance. Usually by the time damage is seen they have moved onto
uninfected tissue. There is a product made by Bayer Advanced which
contains a fungicide, insecticide, and miticide, and is safe for use
on Orchids. It is called (rather unimaginatively, but to the point)3-
In-One Insect, Disease& Mite Control. Many nurseries will carry it.

There is also a rather mysterious infection of Phalaenopsis called
"microfungus" which is similar in appearance. It generally appears on
semi-mature leaves first and then spreads, and is often accompanied by
a chlorotic appearance. I'd say you should isolate your Phalaenopsis
that show damage, and give them two sprays with the Bayer product.
Wash down your growing area with a 10% bleach solution, just to be on
the safe side. It the problem continues to spread, throw out the
infected plants rather than risk spreading it to more of them. False
spider mites will infest a broad range of orchids, this "micorofungus"
disease only affects Phalaenopsis.

As for the rotted leaf, I suspect that your Phalaenopsis are going for
too long between repotting or not being watered properly. A healthy
Plalaenopsis plant should have at least 4 leaves. A two leaf plant,
unless it is a young seedling is under stress.

Sincerely,
Dennis

[Lily]

Thanks for the advice, I am glad you are still there. I got the
spray and the one leaf looks better even after the first spray. I
really appreciate your advice. I am going to repot but I am not sure
if I should wait until it has another leaf or if it is best to do it
now. Also, when I repot, what do I do about all of those roots that
are sticking out - do I cut them off or put it in a bigger pot so that
they are under the mix? I had cut back on the watering until they
were really dry because I thought that I was keeping them too damp.
Again, thanks so much. Lily

[orchid doctor]

Lily:

If you look on the right side of the home page, you will see a heading
"techniques/culture". Click on this and you will see a couple of pages
I wrote that should answer your questions. One is on watering, and the
other is on repotting. If they do not provide the information you
need, get back to me.

Dennis