Dendrobium losing too many leaves

[tedpoe]

I have several dendrobiums divided from an original I bought years ago. Recently, two of them started losing all of their leaves. No conditions have changed. I water (and drain) weekly; they're happy in a south-facing window with a light-filtering shade to protect them from direct summer light. Looking through references, I can't identify the symptom. Slowly, over the last few months, their leaves have individually turned a dusty silver/white, then dried out and fallen. The stems are firm and the roots appear normal.

Attached is a photo showing the texture of the leaves, but the flash masks the green with the fine silvery color.

Any ideas from anyone would be appreciated.

Thanks,
Ted

[Ross]

Photo? My experience with Dendros has been dismal for anything other than total desciduous.

[Lagoon]

Sounds like spider mites. A photo would be most helpful.
Welcome aboard Ted

[tedpoe]

Sorry, I thought I'd attached it to the post. It was just a bit too large...just getting used to the board.

Ted

[camille1585]

I don't really know what the problem might be, since I'm not a dendro grower (they hate me). If you say the leaves get a dusty silvery white, it could be a sign of spider mites.(just throwing out ideas here!) The canes are still plump, so it looks like the roots are fine.
Also in your first picture, I think I see some thing good happening. What's that little green speck half way down the cane at the front of the picture? Might be a new growth!

[calvin_orchidL]

Welcome to the boards!!

I have had this 'silvery-white' problem re-occur several times with my dendrobiums and to a lesser extent, catt relatives, although for me, this discoloration is always on the underside of the leaves. I've discovered that the main culprit seems to be thrips - if you look closely, you may see little black pin-head-sized balls that can be scraped off the leaf - this is their feces. They like to hide in between the leaves, but occasionally you'll see one or two wandering around. Spray with safers or something and they will go away, although the silver stays.

If it's not thrips, it could be spider mites as Camille and Gloria suggested. Either way, some sort of insecticidal soap spray is probably the best thing to do.