Environmental Disease Control – Flies

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.

Habits and Characteristics of Flies

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.

Prevention

Houseflies breed in places where garbage or manure accumulates.

• Be sure your garbage cans are equipped with tight fitting lids and have no holes. Wash inside of can regularly.
• Check the garbage storage regularly – is it always neat and clean, or is damp waste allowed to collect on the ground? Even if flies are hatched elsewhere, any accessible waste may attract them.
• Promptly dispose of pet droppings. Regular removal of the dropping will eliminate them as a fly attractant and a breeding site.

A good fly control program begins with good sanitation practices.

• Do not allow food to stand exposed where it will attract flies.
• Properly compost or dispose of grass clippings.
• Indoor fly control is much more effective when windows and doors are tight fitting. Windows and doors that are equipped with 14 mesh screens will effectively keep out the housefly. They will also keep out many smaller insects.
• In kitchens, keep the counter surfaces clean. If you need an insecticide to control the flies in your home, apply a household spray or aerosol. Be sure the label indicates the spray is for flying insects. Be extremely careful in using insecticides. Insecticides are poisonous to man and animals – follow the directions on the label. Remember a little goes a long way.
• Fly swatters are still one of the best methods for control of the occasional fly pest. Keep one handy.
• Flypaper is also an effective fly control measure – the fly is attracted to it and once it lands on the sticky paper is unable to escape.