They move readily from tree to tree but normally only for short distances, usually no more than 200 or 300 yards. The flies are not particularly attracted to apple fruits during this period and may be found in unfruited trees and shrubs in and around the orchard. At the end of the preoviposition period and after mating, the female flies seek out the fruits. They place the eggs just under the skin through a puncture made by the sharp, needlelike ovipositor. Females may lay eggs over an extended period of time.
Eggs usually hatch in less than a week.
Maggots hatching from these eggs tunnel through the apple, causing a breakdown and discoloration of the pulp. The mature maggots leave the fruit and enter the soil, where they transform to the pupal stage. Most pupae remain in the soil until the following summer. They emerge at the normal time during the second summer. These are not of much significance to growers who maintain good control every year, but they might be of importance in an orchard where the pest was allowed to become very numerous.