I don't have issues with AM's . Working with WSU they say they do not hit pears but there is a look a like that does. They say get rid of the early cultivars and any Hawthorne trees in the area , their number one target. Locate your orchard as far as possible from other orchard stock as the prime method of infestation is immigration . Trap the perimeter . The flys lay their eggs and the larvae drop to the ground and burrow to pupate. So disrupting or treating the soil is essential.