Cherry Fruit Fly and Black Cherry Fruit Fly
Description and life cycle
These flies are slightly smaller than the common house fly and have wings marked with distinctive black bands. The cherry fruit fly female has four white bands crossing the abdomen lacking in the black cherry fruit fly. Maggots are creamy white, legless, tapered at the head end, blunt in the rear, and reach 5∕16 inch at maturity.
Both species have one generation per year. Adults emerge from the soil in June and July. The black cherry fruit fly emerges about a week before the cherry fruit fly. Females lay eggs in cherries over a 3- to 4-week period. Newly hatched maggots burrow into the fruit as they feed on the flesh. There are three larval instars lasting a total of 10 to 21 days. The last instar emerges from the fruit, falls to the ground, and burrows down 3 inches where it pupates.
Maggot-infested fruit is often shrunken and misshapen, ripens earlier than surrounding fruit, and is unmarketable.
Monitoring and management
Adults can be monitored using adhesive-covered yellow panel traps baited with an ammonium-carbonate lure. Traps should be placed in the fruiting canopy of the tree, with fruit and foliage removed from around it for 12 to 18 inches. Traps are used to detect the beginning of fly emergence, but they are not good indicators of the level of infestation.
Management is directed against the adults because once the maggot burrows into the fruit it is protected from insecticides. Insecticide treatments should begin about one week after the first fly emerges. A long-residual insecticide should be applied every 10 to 21 days until after harvest to kill adults before they can lay eggs.