Posted: 20/04/2015 at 11:45
I'm no expert but had a plum tree on my last allotment, I'm given to understand two things need to happen for it to fruit. It needs to blossom but a late frost can kill the blossom in which case there will be no fruit. Secondly the blossom needs to be polinated and so bee's need to be encouraged to come.
Are the branches conjested and crossing over? My tree was in need of a sever prune and so in the autumn it was cut back a third, all the crossed branches taken out and branches I couldn't reach to pick fruit.It was a very sever pruning but produced a pumper crop.
Does your apple tree have ants on or around the stem, these can farm aphids. ,