The apple maggot fly (AMF) lays eggs and little tiny larvae burrow through it leaving brown tracks. I have no problem eating those apples, but most of those apples fall off the tree before I get to them, and the remaining apples rot after a short time in storage.
Acetamiprid has allowed me to have a halfway decent apple harvest from a home orchard for two years now. It doesn't seem to kill the adult flies so the fruit is still blemished, but it appears to kill the larvae as there are many fewer brown tracks and the apples keep in my cool basement until mid winter.
The alternatives are organophosphates, which are nerve gas precursors or pyrethroids, which are much more bee toxic.
But the categorical dismissal of the use of pesticides in growing fruit along with the high moderation points -- have people around here ever tried to plant an apple tree and get usable amounts of fruit from it?