The flies constitute one of the largest orders of insects, and one of the most diverse. Unlike other insects, true flies have a single pair of wings with the hind wings reduced to a pair of knob-like appendages called halteres. Flies occur in most every habitat imaginable…some breed in pools of crude oil, many species make their living sucking the blood of other animals, and some are parasitoids (they develop inside other insects, killing them in the process). Many flies are important in disease transmission, and have had tremendous impacts on human populations. Still others are beneficial - pollinating various plants, serving as important decomposers, or keeping numbers of other insects in check.
Entire volumes are devoted to the identification and life histories of flies (and some entomologists, formally known as Dipterists, spend entire careers studying them!). In this limited space, I’m just going to point out a few that can be an annoyance in the home.
Fungus gnats sometimes occur in large numbers in homes. These tiny insects are harmless and can be found outdoors most anywhere moist, decaying organic matter occurs. Indoor infestations are usually the result of loose-fitting screens or windows, or gnat populations building up in overwatered houseplants. Control is relatively simple – if the gnats are coming in from outdoors, identify the point of entry and seal it up! If the gnats are breeding in houseplants, reduced watering is recommended. An easy way to accomplish this is to stop watering plants and observe them carefully – at the first sign of wilting, water lightly, and keep watering lightly thereafter.
A fungus gnat…
Drain flies are small, annoying flies that resemble tiny moths. They can often be seen resting in a vertical position on walls near infested drains. The larvae of these flies feed on the gelatinous organic slime that builds up in drains. Again, control is pretty simple…cleaning drains removes the organic slime that serves as a food for the larvae. Drain cleaners may give variable results – most pest management professionals have access to biological products containing enzymes and beneficial bacteria that “digest” the material in drains. These flies are harmless, but may be an indication of a more serious plumbing problem such as a leaky or broken pipe.
Drain flies look like tiny moths.
Finally, everyone’s familiar with fruit flies! These tiny flies may or may not have red eyes, and can be seen hovering around overly-ripe fruit or vegetables. Other sources may include fermenting materials such as accumulated beer cans (college students take note!). A simple way to keep fruit flies from breeding in stored recyclables is to rinse containers before placing them in the bin. Insecticides are generally not needed to control fruit flies – simply removing the breeding material is sufficient.
Time flies like an arrow….fruit flies like a banana!
Countless other flies may bother homeowners. Some can be an indication of a dead animal nearby (flesh flies) while others can breed in decaying vegetation such as grass clippings in the yard (eye gnats). Biting flies such as stable flies, horseflies, and mosquitoes are not covered under standard household pest agreements as they breed in outdoor environments and can fly great distances. Love ‘em or hate ‘em, flies are fascinating creatures with an incredible variety of lifestyles!
As always, thanks for reading! Next time, I will discuss moisture issues that can impact pest prevention programs.