At 1/8-1/4 of an inch in length, house flies can be readily identified by the four lengthwise stripes on their thorax, directly behind their head. Adults cannot bite as their mouth parts are adapted to be utilized in a sponging method which limits them to ingesting only liquid foods. Solid foods are liquefied by regurgitating saliva onto the surface and then sponging up the resulting liquid with their proboscis. Commonly feeding on fecal matter, open and infected wounds or sores, sputum and miscellaneous moist decaying matter such as spoiled meats, house flies are certainly not the cleanest of insects. Regular visits to places like landfills, sewers, garbage containers and agricultural areas are part of the reason that house flies are strongly suspected of transmitting more than 65 diseases. House flies habit of regurgitation and excretion mechanically transmits disease organisms.
Females deposit approximately 100-150 eggs onto material that will provide adequate food to the hatching larvae. This may include decaying organic material such as grass/plant matter, garbage and either human or animal waste. Eggs hatch in as little as 7.5 hours or as long as two days depending on environmental conditions such as temperature. Emerging maggot larvae lack defined heads, eyes, antennae and legs. They are worm-like creatures that have a pointed front end of their body that gradually widens towards their rear. They immediately begin feeding on the material surrounding them. Larvae develop through three molts with mature larvae burrow into surrounding areas and begin their pupation. Adults emerge from inside the reddish-brown encasement of the pupae and breed within a day or two. The life cycle of a house fly from egg to adult can take as little as one week in optimal conditions, but more commonly occurs in a three week period. During warm summer months adults live an average of two and a half weeks; however, in cooler winter months adults may survive up to three months, allowing them to overwinter.
House fly control consists of four basic principles: sanitation, exclusion, non-chemical measures and chemical control in that order. Sanitation is the most important aspect of limiting house fly populations as lack of food sources can greatly limit their ability to breed. Avoid allowing the buildup of decaying material in and around the home or building. This includes the clean up of animal waste, decaying plant material and garbage. Trash cans should be cleaned on a regular basis and kept tightly sealed to prevent eggs from being deposited. Exclusion to keep house flies from entering homes and buildings is the second most important method of control. Window screens should be tight fitting and not contain holes or damage that will allow flies to pass through. Seal gaps around utility penetrations and inspect/replace weather stripping around doors and windows as needed. Ventilation is important to buildings; however, proper screening is needed to prevent house fly entry. Non-chemical control methods include ultraviolet light traps, sticky fly traps and of course fly swatters. Not all of these methods are economical for a home environment however. Chemical control methods may assist in the initial knockdown of fly activity, but are rarely a long term solution. Chemicals often break down and are restricted for use in specific places which makes fly control difficult since flies do not typically crawl across long distances of surfaces as other insects typically do.