I have a different problem with my sour cherries I thought I would post here. I have two sour cherries (Montmorency and Morello) on dwarfing Giessen rootstocks in containers on my roofdeck (8th floor) in Chicago. Last year, they both got horrible powdery mildew followed by mite infestation (I understand one can follow the other). I tried a milk spray I read about, soap spray, and finally a neem spray. Nothing seemed to provide complete relief. Unfortunately, the mildew and mites started to infect my apple trees, which proved more resistant, but still suffered. Now, it is important to add that these poor trees started off the growing season on a covered balcony until we moved to our roofdeck, so I am wondering whether the lack of direct sun caused the problem in the first place (everything stayed wetter longer, etc.). Is there anything I can do to prevent th return of mildew/mites this Spring? Or should I toss the cherry trees in the interest of healthier apples? Thanks for any advice.