Yellowing leaves on Onciduim?

[silken]

Using a magnifying glass to inspect the underside and crotches of the leaves should tell you if it is spider mite. Holding the plant up to the sun too will reveal the fine webs and tiny mites moving around.

[Wjs2nd]

I have a different kind of onc. with rat-tail leaves. However, with the yellowing I've seen before this looks like it could be normal. You can do a preventative spray like tucker85 suggest and you can also cut the yellowing leave(s) if they make you nerves. Just don't cut off all your leaves. Good luck.

[greenpassion]

Don't know if the photos show it well, but there is one of a psuedo (?) bulb and the yellowing is from the top of that on into the leaf....

[silken]

Did the roots look good when you re-potted? What type of potting media is it? I know you said for oncidiums, but where did you get it and what is it made of? Some of the stuff bought in places like Home Depot say they are orchid media but are much to fine and dirt like for most types of orchids. It should be fairly open with small or medium pieces of bark, or coconut husk and possibly some moss, chunky perlite, etc.

The pseudobulbs should be green and fairly plump although some of mine do have some wrinkles which I can't seem to prevent. Old bulbs and leaves will turn yellow and die eventually and should be replaced by new growth. It just should look like natural dying off of the oldest ones.

I see lots of brown spots on the yellow leaf in one photo and therefore you should inspect it closely to make sure there are no pests. You need to get your nose and eyes in there and give it a close inspection. If there are no pests and the roots were good and it is potted in good media, then you likely have nothing to worry about. And I would get a skewer and gently wiggle it in there and leave it. Every time you think it needs water, pull it out first and check. They should be close to dry before watering. Hope that helps.

[greenpassion]

Thank you Silken. It is potted in Orchid Web's classic potting meduim for Oncidiums. It came to me in what seemed like regular potting mix, or maybe the Miracle Grow mix, which is too much like potting soil. I've had this plant for about a month now, in the good mix. The roots looked good when I repotted it. I have examined this plant obsessivly, daily, and can't see pests. I may have to wait and see.

[silken]

I have never bought from Orchid Web, but am familiar with their site. I am sure the media is fine. New media doesn't absorb water as well as media that's been in the pot for a while so it may need more frequent watering for the first few months. It sounds like it will be fine. It may just be old age of that pseudobulb or the stress of moving to a new home and being re-potted etc.

[greenpassion]

Thank you for your help. I apprieciate how quickly you get back to me.