Common Fruit Flies

APPEARANCE & IDENTIFICATION

Fruit flies are small flies that often are seen flying around the food they eat and the sites they develop in. They are about 1/8 to ¼-inch long and their body color ranges from tan to brownish-yellow or black. While not a characteristic of all fruit flies, their eyes are usually a bright reddish color. Fruit fly larvae are white or cream colored, about the same length as the adults and are often very hard to see in the locations in which they develop.

BEHAVIOR (ACTIVITY)

Since fruit flies are attracted to light, they can be seen at windows, sinks, on walls and other locations where natural and electrical sources of light are present. However, fruit fly adults generally do not move very far from their feeding and developmental source near the surface of fermenting foods, moist organic matter and in drains. Fruit flies can be a problem year round for homeowners, especially in the kitchen, but are more likely to become pests during late summer and fall.

As one might suspect, fruit flies are able to mechanically transmit filth-related disease organisms by picking up these organisms on their legs and body while in their primary developmental and feeding sites. Therefore, they can subsequently transmit those organisms to people by contaminated foods, kitchen surfaces and food preparation equipment. Local health departments are very concerned by the presence of fruit flies in commercial facilities and have strict sanitation standards in place.

DIET

Fruit flies eat just about any fermenting organic matter.  Their more common sources of dietary requirements are over-ripe fruits, vegetables and fermenting liquids such as beer, wine and soft drinks left inside empty containers. However, not all of their preferred foods are quite as obvious and easy to find as those listed above, since fruit fly larvae will also consume the slime and food items found in dirty drains, trash receptacles and unclean garbage disposals. In general, if there is a fermentation odor and moisture, fruit flies are attracted to feed.

HABITAT

In general, the typical habitats of fruit flies are those locations that support the developing larval stage. In other words, just about any place where fermenting foods and moist organic matter occurs can be an ideal fruit fly habitat.

REPRODUCTION & LIFECYCLE

Fruit flies develop by complete metamorphosis and go through four stages in their life cycle – eggs, larvae, pupae and adults.  These insects are very proficient at reproducing and complete their life cycle in as little as 8-10 days. Their life cycle begins with a female fruit fly sometimes laying up to 500 eggs in a suitable developmental site and within 3-6 days the eggs hatch and become feeding larvae. Within a few days, the larvae molt to become pupae and the pupae crawl to drier areas where they develop into adults.

SIGNS OF THEIR PRESENCE (COULD BE DAMAGE)

Flying adults flitting around fruit or resting on walls are the most obvious signs of fruit flies. Over-ripe fruit and vegetables, among other sources of moist organic matter, are indicators of a possible fruit fly problem in the making.

PREVENTION TIPS

The most effective preventive measures are to eliminate all fruit fly habitats.  This is accomplished by cleaning the inside of drains to remove organic matter, disposing of fruit and vegetables that are over-ripe, rinsing out and disposing empty bottles and getting rid of anything else that is attracting fruit flies. Sometimes, homeowners resort to flushing bleach or boiling water down a drain in hopes of killing fruit flies; however, this doesn’t completely work since the drain pipe may still have the organic matter slime on the sides and fruit fly larvae will continue to develop quite well.  Also, keeping fruits and vegetables in the refrigerator until they are used will help prevent fruit fly problems.

If one continues to have fruit flies after taking preventive actions, one must check all potential developmental sites and eliminate them by cleaning and drying them out. A homeowner can inspect for fruit flies coming from drains by putting and taping a clear food wrap such as a sandwich bag over the drain. If that drain is a fruit fly source, within a few days the adult fruit flies will be visible under the clear bag or else stuck to the tape.

HOW TO CONTROL

As mentioned above, the primary prevention of fruit flies involves eliminating their sources of food and keeping things dry. Other techniques to help control fruit flies include:

  • Using homemade or commercially available traps to capture fruit flies.
  • Using heavy duty drain and floor cleaners to remove drain slime and clean floors.
  • Using aerosol insecticide sprays to kill adult flies. While this is a permissible technique, the product must be used in strict accordance with the label and with the understanding that sprays are only a temporary solution.
  • Sometimes, self-help methods are not sufficient and it is necessary to contact your pest management professional for help with resolving fruit fly problems.