House Flies

Within the last week we've had several calls about large populations of flies in residential areas. Seems like a good time to revisit fly habits and control, with an eye to giving homeowners a few helpful hints.

The "house fly" or musca domestica is one of the most common of the thousands of species of flies. When more than the usual number of flies begin to invade a house, control requires some education and a little detective work. Adult flies are pretty easy to kill with over-the-counter bug sprays or an old fashioned swatter. But the problem will not abate until the source of the flies is discovered and removed. Flies can multiply rapidly because of their rapid development time and the large number of eggs produced - several batches of 100-150 per female. Eggs are laid in warm, moist areas, often associated with decaying organic matter such as manure, grass clippings, garbage, damp leaf litter, or decaying fruits or vegetables. They also appear in great numbers when an outdoor pest such as a rodent has died. Eggs hatch into larvae, or maggots. Fly larvae resist light, and typically burrow into the decaying matter from which they hatched. But in cases where flies are abundant and breeding is undisturbed, the maggots may be obvious. In the larval state, these pests are not even slowed down by the liquid chemicals applied for control of other household bugs. Therefore, control of flies is affected by control of the harborage site where flies are breeding. 

The first step in control when flies are invading a house is to check screens and weather stripping on doors and windows. Outdoors, clean up dog feces, rotting fruit, grass clippings, or any other decaying organic matter that may be attracting flies. Homeowners should check garbage cans, cleaning them to remove residual waste. In multiple-unit complexes where dumpsters are used, the dumpster company should be notified if there is fly activity, so a clean replacement can be provided. In both cases, garbage should be bagged before disposal, and cans should be in good repair, with tight-fitting lids. After all these preventive measures have been completed, the residual adult flies can be controlled with fly strips or bug sprays. Again, poor exclusion and/or sanitation are most often the cause of indoor fly problems. Save yourself some frustration by examining the area surrounding your home and eliminating the source of the infestation. For an effective method of killing random flies barehanded, click here. To read an article in Science Daily about how flies react to odors, click here.