Although I have no experience with fruit trees, I spray neem oil on everything for every issue: slugs, cabbage moths, blight, you name it. It works on everything except large critters.
My maple tree is not looking good this year. I thought my neighbor might have hit it accidentally with Roundup over spray and wounded it and/or maybe it's suffering from some bugs or disease.
I'm not a better living through chemicals kinda guy and don't want chemical warfare in my yard, but neem oil might be exactly what I'm looking for.
Also, have you ever used AzaSol? From a web search: "AzaSol is the water soluble powder azadirachtin extracted from the Neem seed."
Now I just need to find a cheap sprayer that can shoot 20' or more to hit the upper leaves.