Sunny - most probably it is a powdery mildew and it happens when the plant doesn't have enough air circulation and there is a significant temeperature drop in the night.

Out of simple measures - I would remove all bloom stalks - old - new and buds, wash the plant in a sink under the lukewarm water, let it dry blotting the center of the crown with a paper towel - and then - either - spray everything with a Lysol desinfectant spray, or mix water and milk - let's say 4:1 - and spray the plant. Let it dry - and may be find a different location for it with more air movement.

You can read about powdery mildew - and there are lots of remedies against it - but what I suggested is easy and harmless.

Good luck

irina

Hi Sunny,
I think that air circulation is the key to keeping plants safe from powery mildew. To that end I have a ceiling fan runing 24/7 and an oscilating fan on when the lights on my stands go on. As Irina said, Lysol disinfectant spray works to remove the mildew but it kills the bloom wwhen sprayed so you eventually have to remove the bloomstalks. I have never had to immerse my av's in water. Usually the Lysol and air circulation does the trick.
Fred in NJ

Fred - thank you for correction.

Oops - language barrier..

I do not sink my violets in the sink ;-))

I shower them with the sink sprayer low strenght tepid water - I hope most of the spores will be dislodged this way and go down the drain.

I was really impressed by Lysol. I have a Japanese streptocarpus - Hototogishu - and it gets PM on the leaves in spring. I just sprayed directly on the spots - repeated it in a week - and it disappeared.

Irina

Thanks irina and fred. I`m going to try lysol. I`ll let you know how it goes. My av`s were close to each other before and I`ve since separated them . But the powdery mildew still comes back. Lysol it is!
Thanks,
sunnybun