I have a flowering crab (apple?) tree. It is approximately 15 yrs mature. This spring it was magnificent, but now it has a fungus. Leaves are all spotty, turning and falling off prematurely. I have a fungiside that says to begin treatment in spring just before blooms open. Do I leave the tree now and do nothing, or is there something I should do. I also skipped pruning it as I am afraid to with this fungus compromising the trees health. Can you advise me on what course to follow. Thank you.