Hello. I found your site while googling "african violets." I love them! They are the only flower I have't been able to kill. I have nine plants--all noids--and have even started plants for friends.

I do have a problem, though. One of my plants--in fact the oldest--has a white powder all over its beautiful dark purple flowers. It has been this way for about 18 month. The powder is never on the leaves. It is a very vigorous plant, and I have not seen any signs of the powder on my other plants. When the flowers open, they are fine. The powder shows up about 24 hrs after the bloom opens. It has some characteristics of powdery mildew, but not all. What is this and is it threatening to my other plants? How do I treat it? Can I treat it?