Yellow spots on onc. leaf

[Onyx]

I've been keeping an eye on these spots for a few weeks now, trying to figure out what they are and whether they were spreading. Obviously, googling for "spots on oncidium leaf" doesn't come up with much useful info, haha. They're primarily on one large leaf, but it appears there are now a possibly a couple of tiny ones on a different pbulb's leaf, so figured it was time to ask. In the time that I've been watching them, they haven't grown much if at all, and are only visible from the underside of the leaf. It doesn't appear to be sunken or anything like that, just these random yellow blotches. All these blotches seem to be reasonably consistent in shape, and a few seem to have green dots in the center like they were green eggs on a leaf. :P Not quite a Dr. Seuss line though. What causes this and how should I treat it?

This plant was virus tested a few months back and came up clean and still seems to be doing quite well, growing new roots and all that, but I'll test again if needed. It was near some questionable amaryllises for a week or so, but I don't think there was any physical contact between them (and the amaryllis might just have been nutrient deprived, don't know for sure). I have two other divisions of the same plant and neither have it -- just this large one.

[WhiteRabbit]

[Island Girl]

I'm thinking some type of pest... But I don't know what, so I'll give you a few (really good) links that should help you figure out what it might be. And hopefully someone more knowledgable, & who has seen this type of damage will come across this thread! I would also suggest bookmarking these links as well, b/c they can come in handy, at least, they have for me!

This link is to a Pest & Diseases page that shows signs, symptoms, treatment, prevention:
http://www.houstonorchidsociety.org/...ySueBottom.pdf If you would like to look at more pictures of what certain damage looks like, & at more pics than they have on this PDF, the last link I added will have more pics of damage, in the left-hand side column. 6th link down from the top, under "Pests & Diseases".

On page 12, there is a chart for pesticides, it's really hard to read off of the PDF above, so here's the direct link:
http://www.staugorchidsociety.org/PD...rchidPests.pdf

On page 36, the chart is for Fungicides & Bactericides, & you can't read that either, so while I'm at it, I'll add in that link too, so you can have it, if ya ever need it:
http://www.staugorchidsociety.org/PD...idDiseases.pdf

*All this info & more can be found at: (*the column on the left-hand side of the home page is where more *pictures of damage from pests & diseases) St. Augustine Orchid Society - North Florida Orchid Growing

[NYCorchidman]

I think it's some kind of fungal. As much as I love flower shows of many oncidiums and their related intergeneric hybrids, I hate most of them for ugly leaves.
I had many once, then dumped out all over stress caused by those leaves, only kept clean ones.

Unfortunately, I never had success with fungal attack on oncidiums. If the affected are is small, I always cut off those area. I tried spraying.
They almost always came back and that's when I toss them. lol

My Tiger Crow "Golden Girl" has all of its older leaves spotted with tiny little black specks, which seems very benign and the new growth is coming out all clean.

A recent purchase and very lovely plant, Floral Factor is unfortunately having leaf issues similar to yours, those yellowish circular spots. hmmmm



I know, sorry about not being much of help.