Fruit Fly Facts and Infestation Tips

A Small Orange Nuisance With Red Eyes

Orange fruit fly
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The fruit fly (often called a gnat) is one of the most common, and one of the smallest flies found in the home. It is often brought into the home on fresh fruits and vegetables and sticks around because it finds plenty of food.

If you can get close enough, you can easily identify this tiny fly by its:

  • Red eyes
  • 1/10 to 1/5 inch length.
  • Yellowish-brown to brown body.
  • Black rings across its abdomen

Of course, at 1/10 inch long, a magnifying glass or microscope will be needed to see these minute characteristics!

Fruit Fly Facts

  • Though commonly called a fruit fly, its technical name is vinegar or pomace fly, or even more scientifically Drosophila fly.
  • As you would expect by its common name, the fruit fly feeds on overripe fruits, rotting vegetables, fermenting liquids such as soft drinks and alcohols, and other foods in garbage and drains.
  • Since fruit flies are attracted to the yeast in the foods, they also may hover around or land on breads and other baked goods.
  • As its technical name symbolizes, the "vinegar" fly is also highly attracted to vinegar and pomace (the pulpy residue left from the crushing of fruits).
  • There is usually the greatest number of fruit flies in late summer and fall because that's when there is the greatest amount of harvested fruit attracting them.

Fruit Fly Damage

The fruit fly does not really cause damage in the home—it is just a great nuisance, especially when there are a lot of them. It can, however, damage harvested fruits and carry sour rot organisms to damage vineyards.

This fly can be of particular concern in the harvesting of strawberries to be picked for freezing. Since the fruit is left in the field to ripen, it becomes attractive to the fruit fly while still on the plant, thus making the fruit particularly susceptible to fruit fly damage.

Restaurants are very susceptible to fruit fly infestations because of the amounts of fresh produce brought in and the potential for build-up beneath soda fountains and beer taps. The key to prevention and control is the same as in the home: sanitation and removal of potential feeding sites.

Fruit Fly Control

As with most flying insects, control of this fly is best achieved by identifying, then removing the source of its feeding and breeding:

  • Discard or refrigerate ripening fruits.
  • Clean any spilled juices, sodas, or other liquids.
  • Wash out beverage containers before recycling.
  • Clean garbage and trash containers and areas.

A household pyrethrin aerosol can kill the adult flies, but it will not kill the larvae. For that reason, repeated application is necessary until all feeding/breeding sites and matured adults are eliminated. When using any pesticide, always read and follow all label directions.

Once all feeding/breeding sites are cleaned or eliminated, it can also be effective to simply wait them out, particularly in outdoor areas, because once it turns cold, populations can disappear as suddenly as they appeared in the warm weather!

Commercial Control

There are additional methods of professional control of fruit flies for commercial and industrial applications. These may include restricted-use pesticide application, fumigation, and (as was used on a trial basis of tropical fruit shipped from Hawaii) irradiation. These are not practical for home application, though.