Hi,

I am pretty new in gardening but each year I have half a dozen of petunias window boxes. This year for first time I see some white thing on three of them. It's started with one of them, there of them are completely covered by it now and the remaining three are getting attached now too.
The flowers in the first box are suffering very much and. Am afraid I am going to loose them. Any advice so I can urgently react is very very much appreciated.