by Ric Bessin, Extension Entomologist
University of Kentucky College of Agriculture
Two species of fruit flies attack the fruit of sweet and sour cherries; the cherry fruit fly, Rhagoletis cingulata, and the black cherry fruit fly, Rhagoletis fausta. These fruit flies are closely related to the apple maggot and the blueberry maggot which attack apples and blueberries, respectively.
Cherry fruit fly maggots feed on the fruit of sweet and sour cherries, pear, plum, and wild cherry. Infested fruits often appear normal until the maggots are nearly full grown. Damage appears as sunken, shriveled areas on the surface of the nearly ripe and ripe fruit. Fruits may be blemished by the egg laying punctures made by the female near the bottom of the fruit. On unmanaged trees, the majority of the fruit may be infested with these maggots.
The adults are black flies with yellow heads and are somewhat smaller than a house fly. Between the base of the wings is a white or cream colored dot. The dark markings on the wings are used to distinguish the species. The abdomen of the black cherry fruit fly is entirely black, while the cherry fruit fly is marked with a series of four-white crossbands. The wing marking of these flies is very characteristic and can also be used to distinguish between the two species.
Cherry fruit flies spend ten months of the year in the soil beneath the trees. Adults emerge from late May to early July and lay their eggs in the fruits. Normally, a rainfall sufficient to wet the upper inch of soil is required before flies will emerge from the soil. Dry soil conditions may postpone emergence. The black cherry fruit fly generally begins to emerge about ten to fourteen days earlier than the cherry fruit fly. There are usually 10 days between the fly emergence and egg laying. During this period adults feed on aphid honeydew and other sources. The eggs hatch in about 4 days to one week and the maggots feed for about two weeks. When full grown, they drop to the ground and burrow into the soil. They pupate 1 to 2 inches beneath the soil surface. There is only one generation per year of each fly.
Monitor cherry fruit flies with yellow sticky cards hung in the trees in late May. Examine the traps twice a week to determine when adult emergence begins. Use the banding on the wing to distinguish between the species.
Because the female flies insert the eggs beneath the skin of the fruit, the eggs and the larvae that emerge are protected from insecticides. Sprays need to target the adults before egg laying begins. Adults should be controlled 5 to 6 days after they emerge.
CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication.
Of course, ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY PESTICIDE!