I have attached some pictures of the phals and dends that I have with these blemishes on the leaves... I have them all under the wonderlite. But these blemishes seem to get more widespread (and more and more "blackish")... as if it's rotting that leaf day by day! I thot it may have been a fungi infection at first attacking the roots? But some of the leaves have them and some don't. Further more I've checked the roots of one of my phals, and they seem to be fine... white and semi-good-looking... So help!! :)
Hmm. I suspect spider mites in the center picture (pitted appearance of leaves). How moist do you keep your plants? Black rot can occur in cool, wet conditions---it can go from roots up or leaves down. Phals like a fair amount of warmth. Do not let your orchids stand in water!---Photo on R. looks like a paphiopedilum.
So do you think I water my orchids too often? I water them about every 8-9 days, and I do have them in the house under a Wonderlite. Daytime temperatures run around 80 degrees and nighttime around 70 degrees. Hmmm.... Would I be able to see these spider mites? I have other phals and another dendrobium around the vicinity, and they haven't been affected... yet!! Will they also get these infections?? What should I do?? Fungicide? Or insecticide??
Could be spider mites or false (flat) mites. One leaves webbing, the other doesn't. Try looking on the underside of the leaves.The easiest way to control these leaf-suckers is to simply hose them off in the sink. Since mites have a short life cycle, do this every few days for a while. You can resort to insecticidal soap, but I would try the simple non-chemical method first. Yes, I would move the plant away from others, since mites transfer easily and LOVE orchids. A good idea with ANY plant you have doubts about: prevention is way better than cure!---With your others, they really don't look all that bad. You say your roots are OK---that is a GOOD sign! The color of the phal leaf (photo on L.) could just be normal old-leaf yellowing. And if the orchid on R. is a paph, which I suspect it is, it might do better in nice rich tropical-mix soil rather than bark. (Paphs are terrestrial orchids.) ---Yeah, it's like juggling plates in the circus! You've got to be aware of a bunch of things all at the same time: humidity; temperature; light; bugs; air circulation. But when you get it all working, it's great! Orchids are tough, and I'm figuring yours will be OK. Just use common sense, and do the simple thing first. Good luck!
You will have to be diligent for awhile to overcome the insect life cycle. As soon as you begin your plants will stop detetiorating and start to thrive again. It takes time to build up the energy to flower so it's a battle to maintain your plants leaves and roots to optimum health. I think you have decent lighting (previous post?) so you won't have to wait long to see growth. Good luck Shaun
