My cherry blossom tree's trunk is not looking very healthy and the leaves at the top are being eaten :(
Go to ACE. Get one box of Cherry Blossom Awesome (pink and green box) and follow the directions (it's basically: mix with water, apply and wrap with supplied bandage.) I had several trees in the same condition and within one month, all were healthy again. The box costs about $10 and it works! I think you can get it online directly from the manufacturer too. But I see it at ACE every time I'm in.