Fruit flies, Drosophila spp., can be a common insect in homes during fall. Also called vinegar or pomace flies, they are small, about 1/8th inch long with a brownish body and a dark colored abdomen. Fruit flies typically have red eyes which are a good feature to help distinguish them
|Fruit flies are about 1/8th inch long and usually have red eyes.|
Photo: Jeff Hahn, U of M Extension
Be careful as there are other small-sized flies, such as fungus gnats, moth flies, and humpbacked flies, that could be confused with fruit flies. There is even a couple of species of fruit flies with dark colored eyes that are a little larger than an average fruit fly. The control varies depending on what the type of fly is found so it is important to verify the insect you are finding in your home.
Fruit flies are associated with fermenting, moist, relatively undisturbed organic material. This is often due to overripe and decaying fruits and vegetables but can also be in a variety of other sources, such as soft drink, wine, and beer residue in unclean containers (and have been sitting around for a while) and trash containers with wet garbage that are not cleaned regularly.
These flies can also be found in unusual, unexpected sites. In one case they were found infesting an osage orange that had been set out to control spiders (which by the way does not work) and forgotten about. As it became soft and started to decay, it attracted fruit flies which infested it.
The best control of these flies is to find the source of the infestation and remove it. While this is straight forward, it can be easier said than done. You often have to be a detective to locate the problem as it may not be immediately obvious what they are infesting. Particularly examine areas where fruit flies are found but keep in mind that the infestation source may not always be near where fruit flies are found; it could even be in a different room. Keep inspecting after you find the breeding site as there may be more than one infestation source.
It may be tempting to kill the adults by spraying, swatting or trapping them but this rarely eliminates them. As long as a food sources remains, fruit flies can reproduce faster than you kill the adults. It is very difficult, if not impossible, to get ahead of the problem and eliminate all of the flies by directing control at the adults.