Those white spots that you see if they are powdery to touch are called false mildew or powdery mildew. What I use is a product called safergrow which has cottonseed oil, garlic, and sodium bicarbonate I also add hydrogen peroxide to the mix. Some people use organic milk that is not pasteurized as well. Others have used a sulfur based spray too.Best of luck it is happening to everyone this season alot.