Your question got posted in the wrong place and that's probably why you never got a response. Fertilizer is highly unlikely to help with the problem you describe and is probably more likely to complicate the issue. If you are still looking for answers, I would recommend posting into the main Trees Forum or into the Fruit and Orchards Forum, and I would definitely include a few pictures. You need to ID the problem before throwing a bunch of stuff on the tree and hoping for magic.