Fruit Flies (Drosophila)

Fruit Flies

Several species of Drosophila have been immensely beneficial to mankind because of their use in the study of genetics and heredity.

Fruit flies are attracted to nearly any material that is fermented by yeast. These small flies commonly have bright red eyes, although some species’ eyes are dull-dark red. The head and thorax are yellowish to brown, and the abdomen is light brown to dark with yellow bands. The wing vein structure is important and can be seen with a hand lens. It consists of a thickened vein bordering the front margin of the wing from the attachment at the thorax to the wing tip.

Four other long veins can be seen on the rest of the wing. In a common Fruit fly infestation, flies are attracted to the sweet odour of fermentation in ripe fruit, like bananas;

These small flies (from two different fly families) often are mistaken for each other. They are about 0.3 cm (1/8 inch) long and somewhat similar looking, but their biology and management are very different. Treatment of these fly infestations are a good example of the site specific nature of successful pest management.

Life Cycle


they lay their Eggs in the cracks of the peel. Fruit fly larvae hatch, then feed on yeast cells in the fruit. The life cycle can be completed in not much more than a week.



Newly-emerged adults are attracted to lights, but egg laying females will not leave fermenting materials. Fruits, vegetables, beer, fermenting water from refrigerators, humidifiers, sink drains, sour mops and rags, and fermenting pet food are good examples of fermenting material. Infestations are common in orchards, breweries, restaurants, canneries, hospitals, and homes.



  • When certain the infesting insect is a fruit fly, look for fermenting material. Begin with ripe fruit and vegetables, then proceed to less obvious possibilities.
  • Use fly traps baited with bananas to find the most heavily infested areas when the source is very obscure.
  • Be sure to inspect outside of the building near windows.
  • Drain wet areas around garbage collection sites.

Habitat Alteration


  • Tighten up gaps where flies can enter.
  • Use small mesh screening to exclude these small flies.
  • Discard or clean infested material.
  • Use precautions to remove flies before fruit is brought to terminal points when the infestation originates in the field or orchard. Infestations in canneries and fruit markets are particularly difficult to manage.