Every year I read people whining about the powdery mildew on plants and yes, I am among the whiners. Now people generally assume it is caused by wet circumstances and I know this is not so. It is some combination of wet, dry and day heat and cold nights. Can anyone give me the specifics and any counter measures that have succeeded in minimizing the damage? I know it doesn't usually kill off plants, but it sure is depressing to look at!

This year I began using a spray product before the mildew actually appeared. This is always advised. Yet today, I saw all the signs of it starting on a clematis and had to sigh, wondering if I had invested too much hope in science once again.