Western cherry fruit fly

Western cherry fruit fly larvae tunnel through the flesh of cherries (Prunus species) in mid to late summer, leaving brown trails in the fruit. You will notice dark pupation sites developing on the fruit surface. Adult flies are small, about one-quarter inch long, with banded wings. This is the primary cherry pest in western Washington, requiring harvest-quality monitoring.

Monitor fruit fly emergence in late May to early June using red-ball traps baited with ammonium acetate. Time insecticide sprays to early June through mid-July period. Use spinosad or pyrethrins on edible fruit; follow harvest interval guidelines. For ornamental cherries, accept minor damage or cover fruit during peak egg-laying.