Powdery mildew? Already?

[Don1971]

I always have a big problem with powdery mildew but much later in the year (Cleveland OH). I think I have it already? Note that I cannot rub it off (well maybe a little if I rub hard and for a while). If memory serves me it rubbed off easy.

I really hope it is not or I am in big trouble.

 

[Don1971]

Also this literally popped up overnight.

 

[Don1971]

If it is lets here some ideas to prevent it, and slow it down. I can water less and I have used milk/water mixture - definitely slowed it down. I cut off infected leaves and keep plants spaced far apart but nothing stops it, just slows it. Lots of work to delay inevitable.