I have 2 apple trees in large containers I was keeping alive until I got a house. Its been a year now since I got them at the nursery as 5 gallon trees and planted them in containers. They are covered in what looks like apple powdery mildew. I have treated them with fruit and tree spray a few times but they don't look any better. Should I give up and throw them out? Can the mildew transfer to mynew veggie seedlings? Thanks for any help!!