I don't think mites is likely because there is no indiction of mites- no webs, no red spots, etc- thank you for the test- I tried it and no stripes. I also am unsure of powdery mildew because it is only on the leaves, not the base nor trunk. I also have 2 of the same plants purchased at the same nursery- see pic- they aren't touching but have the same problem. Any advise- can I try to clean some way or dispose and start over?