Primarily active in the summer and found in more places on the planet than virtually any other insect, the house fly accounts for more than 90 percent of all flies in human habitations. Despite relatively short adult life-spans of two weeks to a month, house flies produce huge broods that can quickly lead to infestation. With a well-earned reputation for spreading disease and an increasing immunity to pesticides, house flies may pose serious health threats to humans and pets.
Adult house flies are usually gray or black and can be distinguished by the four black lines running across their thorax. Adults measure 4 – 8mm in length and have hair-like projections covering most of their bodies. Typically, females are larger than males but both have red, compound eyes and sponging-sucking mouths used to eat liquid and saliva-dissolved food stuffs. House flies are active during the day and will hide or rest in high places to avoid detection and threats.
House flies eggs are typically laid amongst larval food sources and hatch within a day. Known as maggots, the fly larvae are pale white, 3 – 9mm long and legless. After 14 – 36 hours, maggots will move to a cool, dry spot and transform into reddish-brown pupae from which adults wills then emerge. Females can mate as soon as 36 hours after emerging from the pupae.
House flies are extremely resilient and are known to survive even harsh winters by hibernating until the first thaw. Large concentrations are often found near food sources both inside and outside of homes. A single house fly can lay 500 eggs, often in garbage, rotting food or in animal feces. Although adult flies have a life expectancy of only 25 days, more than 12 generations can occur over the course of a single summer.
Spotting a house fly infestation is the first step to complete removal. Given the ease with which house flies can multiply, identifying even a single fly can mean a problem is at hand. If you are unsure as to where the flies may be nesting, do a complete search of your garbage, pantries, and pet food bowls. Since house flies prefer dark areas to nest, be sure to check in crevices and underneath appliances where food may have fallen.
Once the breed site has been eliminated, consider fly bait, traps and/or insecticide to eliminate the remaining adult flies. Keeping your home and yard clean, regularly removing garbage and animal waste, and keeping doors and windows screened are all excellent preventative measures.
House flies are capable of carrying and transmitting more than 100 pathogens, including parasitic diseases, bacterial diseases and viruses. Flies intake a large amount of food and may subsequently transmit disease through the saliva and vomit used to soften that food. Additionally, house flies defecate virtually every time they land, creating yet another potential source of contamination.