By introducing apple trees to apple maggots, we will have a situation where the prime food source of the apple maggots will come to them. In that case, the apple maggot's population will significantly increase because they will have their prime food source in abundance. On the other hand, the apple trees will suffer, they will get diseased, damaged, and by losing their leafs they will not be able to perform the photosynthesis process, and that will result in no production of fruits, as well as weakening the tree itself.