[Pest Profile] House Fly

Order/Family: Diptera/Muscidae
Scientific Name: Musca domestica Linnaeus

Description
House flies are 1/8- to 1/4-inch long. They are dull gray with four dark stripes on the back of the thorax. They have two wings; the fourth longitudinal wing vein has a sharp upward turn. The head is dominated by large red-brown compound eyes surrounded by a light gold stripe. Short antennae emerge from between the eyes. Mature house fly larvae or maggots are spindle-shaped and creamy white. They have dark mouth hooks at the head end and breathing slits that look like a wavy “W” at the larger round tail end.

Biology
Female house flies lay their eggs singly but in clusters of 75 to 150 eggs in a variety of moist, rotting, fermenting organic matter including animal manure, grass clippings, garbage, spilled animal feeds, and soil contaminated with any of the above items. A female may lay more than 500 eggs in a lifetime. The eggs hatch within a day, and the young larvae burrow into the breeding medium and complete development in three days to several weeks depending on the temperature and quality of food materials. Larvae migrate to drier portions of the breeding medium to pupate for three days to four weeks before emerging as adults.

Habits
Adult flies may migrate to uninfested areas up to 20 miles away, but most stay within two miles of the breeding site. Adult house flies have a general appetite, feeding on foods ranging from excrement to human food. They feed on liquids but can eat some solid foods by liquefying it with regurgitated digestive tract fluids. During the day, house flies rest less than 5 feet above the ground and at night they rest above this height. House flies have been associated with many filth-related diseases and so are a significant health concern.

Control
The initial inspection should focus on identifying the fly (adult and/or larva) causing the problem and location of all resting and larval development sites. Because adults often rest in breeding areas, it is helpful to inspect at night. Sanitation is the most important step because it eliminates breeding sites. When successful, it significantly reduces the need for pesticide applications. If trash cans are the problem, property owners should be instructed to empty and clean them at least weekly. Mechanical control measures include insect-proof garbage containers, self-closing doors, screening, caulking and air curtains. Operating insect light traps indoors and at night is effective in controlling adult flies inside structures. Sticky traps and other devices are also available to reduce adult fly populations indoors and out. Any insecticide applications should be directed at adults.