Adults are 1/8” long and dull yellow brown to dark brown. Many species have distinctive red eyes, and the wings have two “breaks” in the leading edge nearest the body. The larvae are small (1/10 – 1/5 inch long) and very distinctive with an extended, stalk-like breathing tube at the rear of the body. The pupae are brown and seed-like with two horn-like stalks at one end.
Fruit flies are common structural pests frequently associated with fermenting fruits and vegetables. They easily develop in over-ripe fruits or other foods, fermenting liquid in the bottom of garbage cans, a dirty mop, or a rotting potato or onion in the vegetable bin. Recycling bins and fruit and salad bars are ideal habitats and have resulted in increased problems with this pest fly. Recently emerged adults are attracted to light.
Fruit flies are best controlled by locating and eliminating the breeding material. The presence of adult flies indicates that the larvae are developing in some nearby fermenting materials. Complete and thorough sanitation is necessary to eliminate the source of the infestation. Insect light traps and baited jar traps fitted with tops which permit fly entry and prevent escape are effective in reducing the population but are no substitute for sanitation. Several species are small enough to pass through typical screens, so a smaller mesh may be required. In some situations, an aerosol can be used to knock down adults.