Adult fruit flies are 1/8-inch long and dull yellow-brown to dark brown. Some species have distinctive red eyes, and the wings have two “breaks” in the leading edge (vein) nearest the body. The larvae are small (1/10 to 1/5-inch long) and are 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.
The eggs are laid onto the surface of fermenting fruit or vegetables, or areas where moisture and yeast are abundant. The eggs hatch within 30 hours. Each female produces up to 500 eggs. The larvae complete development in five to six days and crawl to drier areas of the food or elsewhere in order to pupate. The life cycle (egg to adult) requires eight to ten days.
Fruit flies are common structural pest 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 their contents 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.