The eastern cherry fruit fly, or Rhagoletis cingulata, is an abundant pest found frequently in the eastern United States and southern Canada. Its primary wild host is the sour black cherry, though it sometimes infects other fruit, such as the sweet cherry, pears and plums.
The eastern cherry fruit fly is slightly smaller than a regular house fly with a yellowish brown head and legs. It has clear wings with wide, irregularly-shaped, dark bands. Females have four white crossbands on their abdomens while the males have only three.
The flies lay eggs by piercing cherries and leaving the egg just inside the skin. One female may lay over 350 eggs in one mating season. Eggs typically hatch within a week, producing small, headless, legless larvae which burrow into the fruit as they feed and grow. Once the fruit has ripened, the larvae drop from the fruit to the ground where they pupate through the winter. The fully-grown flies finally appear in cherry orchards from May through July. New flies typically feed on aphids and other bugs until they become sexually mature, usually within a week, at which point mating takes place on the fruit.
Damage to Fruit
The initial piercing of the skin normally leaves little damage to the cherry. However, as the larvae grow and feed, the cherries become misshapen and their growth stunted, resulting in fruit that is much smaller than uninfected, healthy cherries. When infected, the skin of the cherries may also begin to shrivel, and as larvae feeding separates the pit from the pulp, the pulp eventually turns brown.
It is important to monitor for cherry fruit flies throughout the season until harvesting, especially in unsprayed orchards. Small larvae can be detected by boiling a cherry from a potentially-attacked tree in water for one minute. If infected, the larvae will detach from the cherry and sink to the bottom of the water. Yellow sticky paper can be used to trap fruit flies early in the season, but the most prevalent method of preventing infestation is the spraying of insecticides seven days after the first fruit fly appearance.