A source for information on flies
The thorax of the fruit fly
is yellowish-tan and the abdomen is gray underneath and black on top. The key identifying characteristic of the
fruit fly is their red eyes.
Fruit flies are small at about
Fruit flies are especially common during late summer/fall due their attraction to ripened or fermenting fruits and
vegetables, but can be a year-round problem. They often lay their eggs near the surface of fermenting foods or
other moist organic materials, where they continue to feed upon emerging. Their reproductive potential enormous;
they can lay up to 500 eggs. Their entire life cycle develops very fast, and can usually be completed within 7-8
Fresh produce and other perishables brought in from the garden or market often attracts fruit flies and causes
indoor infestations. Fruit flies are common in homes, restaurants, supermarkets, or else food is served. However,
Fruit flies will also breed in drains, garbage disposals, empty bottles and cans, trash containers, mops, and
cleaning rags. Adults are strong fliers and have been known to travel as far as 6 1/2 miles within a 24-hour
period. Populations tend to build during the summer, becoming very abundant at harvest time. Indoors, fruit flies
are frequently active at all times of the year.
Essentially, all that is needed for Fruit fly development is a moist film or coat of rotting material. Infestations
can originate from over-ripened fruits or vegetables that were previously infested and brought into the home.
Adults can also fly in from outside from poorly screened windows and doors. Although primarily a nuisance pest,
they have the potential to contaminate food with bacteria and other disease-producing organisms. Any freshly
decaying, moist organic matter that sits undisturbed for five or more days is an optimal environment for fruit
flies. Usually this is associated with fresh fruits and vegetables stored at room temperatures. Once inside, adult
flies emerging from a piece of infested fruit can find and exploit other potential breeding sites such as poorly
maintained trash containers, recycling bins, food kicked underneath tables, coolers, etc., and garbage disposals.
They also may be found breeding in dumpsters outside and flying to and entering the building through doorways. The
breeding media must be continually moist for the larvae to develop and generally in a fairly fresh state of decay.
Any crack or area where organic matter can accumulate can support these flies.
People that can their own fruits and vegetables or make wine, cider, or beer should make sure that the containers
are sealed tight. Otherwise, Fruit flies will lay their eggs under the lid and the tiny larvae will enter the
container upon hatching. They are also called “vinegar flies” since they often infest facilities producing
Fruit fly larvae living in fruit that is then eaten can sometimes cause intestinal discomfort and diarrhea. In
vinegar-producing facilities, the fruit fly is responsible for infecting tanks of vinegar with a tiny nematode
called the vinegar worm. Larvae of fruit flies develop in moist areas where organic material and standing
water are present. The entire life cycle lasts 25 days or more depending on the environmental conditions and
the availability of food.
There are over 500 known fruit fly species across the globe.
Like other fly species, fruit flies experience a four stage life cycle: beginning as eggs, they undergo
larval and pupal stages before emerging as adults. The early life stages span approximately two to
three weeks in ideal temperature conditions. Adult fruit flies can live up to 30 days.
The common fruit fly, or Drosiphila melanogaster, is known for its ability to reproduce rapidly.
The common fruit fly is a useful specimen in scientific research. The rapid life cycle allows researchers to study
the effects of an experiment over a number of generations. Mutations are also common and easily followed in this
fly species. Fruit flies have only four pairs of chromosomes: three autosomal pairs and one pair that determine
sex. The entire compact genome of the common fruit fly was sequenced in 1998.
The best way to avoid problems with fruit flies is to eliminate sources of attraction. Produce that has ripened
should be eaten, discarded, or refrigerated. Cracked or damaged portions of fruits and vegetables should be cut
away and discarded since eggs or larvae may be present in these areas. A single potato rotting in a pantry or a
fruit juice spill under a refrigerator can breed thousands of Fruit flies. The key to controlling fruit flies is
finding the breeding sites and removing them by proper cleaning practices. Fruit flies, like other types of small
flies, can be difficult to totally eliminate because they can breed in such small amounts of organic matter. A
number of breeding sites can be found and eliminated while others may easily be overlooked. The inspection needs to
focus on finding all sites where moist organic matter has accumulated and then removing that matter completely.
Often, in homes, fruit flies are carried in on bananas and when the bananas are removed, the presence of flies
disappears within a few days.
It is also helpful to dispose of trash and store it in a covered container. If you keep a compost pile in your yard
make sure to bury food additions at the bottom. Once a structure is infested with Fruit flies, all potential
breeding areas must be located and eliminated. Unless these sites are removed and cleaned, the problem will
continue to get worse.