Cherry fruit fly

Cherry fruit flies emerge from soil in mid-May in Western Washington, about five weeks before harvest, and lay eggs under the cherry skin. You will see small depressed stings on fruit surface where adults have oviposited; internally, white maggots tunnel toward the pit, creating damage in the flesh. Flies complete development by late July on Puget Sound cherries, apricots, and ornamental Prunus. Adult flies have dark bands across their wings and are slightly smaller than house flies.

Harvest by early July to break the life cycle before flies exit. Remove all dropped fruit immediately. Cover soil with mulch or black plastic after harvest to prevent pupae emergence. Apply spinosad starting mid-May if pressure is high, timing applications early morning or late evening on wet fruit.