We all know that and surely everyone already has one mad apple in hand. If it was only in the hand, it was the least evil. Often you can see the maggots boring into the apples but not biting into the fruit with relish. Well, then you just have a small side dish of meat.
These maggots are the larvae of the apple wrapper, a butterfly that becomes active at night. The maggots get into the fruit because the females lay their eggs on the young plants. The maggots feed on the apples and burrow into the fruit. This can be avoided or at least contained if, in addition to nesting cheeses and birdbaths that should be placed in the garden, you also work with attractant traps that attract male moths. As a result, the population is reduced and fewer females are fertilized and fewer apples are infected.