The fly most frequently associated with man is the common housefly (Musca Domestica). The housefly has long been known to be a carrier of diseases. Among the most important are dysentery, cholera, typhoid, infantile or summer diarrhea, pinkeye, and tuberculosis. Besides these there are about 25 more diseases including pinworms, roundworms and tapeworms that may be transmitted by the housefly. A housefly may carry 4,000,000 bacteria on its body and over 28,000,000 in its stomach.
The housefly thrives in the human environment. It flourishes on the same kinds of food and temperatures as humans, and breeds and reproduces in the wastes left by people and certain animals.
The housefly does not bite, although it is sometimes confused with the stable fly which is a vicious biter.
The housefly cannot eat solid food. The housefly deposits saliva on its food to help dissolve it. It is then sucked up through the proboscis, regurgitated in a single drop and again sucked up. The fly may retire to a quiet spot to clean its head and proboscis, to digest and alternately to vomit and suck up its half digested food.
A housefly will eat anything and everything that is soluble. Any decaying animal or vegetable material may serve as a meal. Breeding places may include fresh horse manure, human feces, animal excreta, and garbage – in fact, any decaying and putrefactive organic matter that is somewhat moist may become a breeding site.
The female fly lays her eggs in clusters of 100 to 150. Normally two batches are laid in a lifetime. Under favorable conditions, as many as 20 batches may be laid by one fly. The eggs may hatch in as little as eight hours. Larvae, or maggots, which emerge from the eggs are grayish or creamy white, segmented like worms, smooth and cylindrical and up to 1/2 inch long. During the larval stage, which usually lasts from 4-7 days, they are highly mobile, feeding voraciously and growing rapidly. At the end of this stage, they migrate from their moist feeding grounds in search of cooler and drier surroundings, such as loose soil or under surfaces of stones and boards, where they turn into the pupa or cocoon stage. In warm climates, this stage lasts from 3-6 days.
The pupa is barrel shaped, mahogany brown, and immobile. Upon emerging, the adult fly crawls about until its wings have expanded fully and are hardened, and its body is accustomed to the new surroundings.
When the fly emerges from its pupal stage, its growth is complete. It is a full-grown, sexually mature adult and will begin to lay eggs in 2-20 days. Although the flight range of most flies is no more than 200-300 yards, some can fly as far as 13 miles from their starting point when carried by the wind. The housefly lives about one month. Many are killed by parasitic diseases. They are rendered inactive by cold and are killed by exposure to a temperature of 10 to 15°F.
Houseflies breed in places where garbage or manure accumulates.
A good fly control program begins with good sanitation practices.