I have a problem with all my apple trees. They flower very well then towards the middle to end of May, when I look at the small apples, some have a small leaf stuck to the side. When I pull this leaf away, I find a small amount of mushy apple (only a very small amount) and when I wipe this off, there's always a tiny hole, only one in each apple.
It starts with just a few apples but by the time middle or late June comes, over 65% of the apples are affected. A lot of these damaged apples drop but it can take a couple of months and some grow to full size but then show signs of bruising where the hole is.