The house fly and other types of "filth flies" can become nuisance pests, because of their potential harm to us and our animals, it is important to know what we can about them. House flies, being the one fly most of are familiar with can spread diseases such as food poisoning and dysentery.Some flies can inflict painful bites while feeding on the blood of humans and other animals,some of these are the stable flies,deer flies and mosquitoes (which are also classified as flies, or Diptera). Some flies like the mosquito and others species can transmit disease.

The feeding habits of filth flies favor the spread of bacteria and other disease-causing organisms. Filth flies will often feed and lay their eggs in garbage, manure, carrion and organic debris. The problem then begins as then they will land on and contaminate human foods and food preparation surfaces. When feeding, house flies will regurgitate their stomach contents onto the food to liquefy it before ingesting it. They will also contaminate food and surfaces by defecating upon them.

IDENTIFICATION

The order Diptera is composed of the "true flies," and is one of the largest groups of insects. Diptera means "two wings."True flies have only two wings (one pair), instead of four wings (two pair) found in most other types of winged insects. All flies are attracted to moist organic material upon which they lay their eggs. This habit makes filth flies valuable as scavengers (mother natures cleaners), but this habit will also bring them in contact with humans.

Filth flies can be divided into two groups, determined by their appearance and food preferences. Filth flies, such as the house fly, blow flies and flesh flies, are relatively small, soft-bodied insects with large eyes. They are strong fliers. Other filth flies, e.g., drain flies, fruit flies and phorid flies, are smaller with more delicate bodies and legs.

LARGE FILTH FLIES

House Fly (Musca domestica)

The common house fly is a dull gray fly, 1/4-inch long with four dark stripes on the middle section (thorax) of its body. House flies typically lay eggs on animal feces and garbage. White, legless maggots (the larval stage) hatch from the eggs and grow to about 1/2 inch. When the maggot reaches full growth, they will crawl away from their food source to undergo the pupal stage. They form a dark brown cocoon, known as a puparium, and later emerge as adult house flies that can fly one or two miles in search of suitable egg-laying sites.

Blow Flies (Calliphoridae spp.)

Blow flies are so-called because the larvae develop inside the bodies of dead animals, causing the carrion to have a bloated appearance. They also are attracted to garbage. Blow flies are about the size of house flies or slightly larger. They have been called ???bottle flies??? because their shiny blue and green color resemble colored glass bottles, though some species are shiny black or bronze. Large numbers of these flies indoors usually indicates the presence of a dead animal such as a mouse or bird inside the structure.

Flesh Flies (Sarcophagidae spp.)

Appropriately named, flesh flies usually seek carrion or scraps of meat on which to lay their eggs. Like house flies, adult flesh flies are dark-colored (gray or black). Common species have three dark stripes on the thorax. They are slightly larger than house flies and have a checkerboard pattern on the abdomen.

Stable Fly (Stomoxys calcitrans)

While not always found in filthy situations, stable flies deserve mention because both sexes feed on the blood of animals, including humans, often biting around the ankles. The bites are painful but are not known to transmit disease to humans. Females lay eggs in rotting straw and manure, moist piles of animal feed and yard waste.

Cluster Fly (Pollenia rudis)

Not associated with filth, cluster flies are mentioned here because they are a common household pest. They also resemble house flies, but hold their wings parallel to the body, not in a triangular configuration as house flies do. Cluster flies are covered with fine golden hairs and have no stripes on the thorax. These flies are unusual in that they lay eggs on earthworms. The larvae consume the worms. In the fall, adult cluster flies often invade homes, especially attics, for a warm, sheltered spot in which to spend the winter. Unlike other filth flies, the principal means of controlling cluster flies is exclusion, that is, sealing buildings to prevent their entry.

SMALL FILTH FLIES

Fruit Flies (Drosophila spp.)

Also known as vinegar flies, fruit flies are attracted to sweet or fermented liquids such as liquor, syrup, soda pop and vinegar, in addition to ripening/rotting fruit. Females lay eggs in and around these materials upon which their tiny larvae feed. The gnat-sized adults typically have tan-colored bodies and red eyes.

Phorid Flies (Phoridae spp.)

Also known as humpbacked flies because of their arched thorax, phorids are tiny, dark-colored flies. The larvae feed on a wide variety of decomposing organic (of plant or animal origin) debris. If suitable materials are present, huge populations of phorid flies can build up quickly. Sources of infestation include liquefied garbage, sewage and carrion, often hidden in places difficult to inspect and access.

Drain Flies (Psychodidae spp.)

About 1/8-inch long, adult drain flies are slightly larger than other small filth flies. Their broad, hairy wings have given rise to another name: moth fly. They also have been called sewer flies, because they infest raw sewage. Drain fly adults are often noticed resting on bathroom walls, in some areas this is why they are called men's room flies. The larvae live submerged in the gelatinous muck that accumulates in floor, sink and toilet drains, by extending their breathing tubes to the surface for air. To eliminate infestations, drains and traps should be cleaned with a wire brush and/or drain cleaner.

Fungus Gnats (Sciaridae and Fungivoridae spp.)

Fungus gnats are relatively delicate, long-legged flies that look like tiny mosquitoes.

The fungus gnat's larvae live in moist places where their food, fungus, grows. Many indoor infestations can be associated with pigeon droppings and with over-watered potted plants where fungi develop. Another place to look is in the bathroom where you have had a leaking pipe. When removing pigeon, bat, mice or rat droppings, take care to wet the area along with the droppings first with a disinfectant like DSV, to kill disease-causing organisms that can be present in the droppings.