Try taking a piece of paper towel. Dampen very slightly with water or
alcohol and wipe the underside of the leaf. If it picks up a reddish or
brownish tint you probably have spider mites.

Try it and let us know.

Bob
"eeyore" wrote in message
...
Found this on the internet. Though the original poster is complaining
about the bug, the white look on the leaves kind of matches
.
http://forum.theorchidsource.com/att...0-05-6_IMG.JPG

"eeyore" wrote in message
...
Hello,

Sorry I can't post photos, but I'm wondering if anyone could identify
what would cause a white, almost powdery look, on the top of the leaves.
This leads to yellow leaves or black blotches on the leaves and then a
dropping of all the leaves. Roots look fine, but not sure what chance I
have with nothing but roots.

Started with my phal's but is expanding to all varieties. Very hot
summer here so at first I assumed it was sunburn, but since it continues
into the fall, it has to be something else.

Hope someone can help, I'm not a scientific grower, just been having a
lot of fun buying orchids that have dropped their blooms for a cheap
price, and getting them to rebloom. I was doing great, until whatever
this is took over.

Thanks!