Domestic flies, often called “Filth Flies,” are not only a nuisance by their presence, but are important from a human and animal health standpoint. House flies may spread diseases such as conjunctivitis, poliomyelitis, typhoid fever, tuberculosis, anthrax, leprosy, cholera, diarrhea and dysentery. They may serve as intermediate hosts for parasitic tapeworms on poultry or parasitic roundworms on horses. Certain larvae of blow flies, bottle flies, screwworm flies and flesh flies may feed on dead as well as living tissue of mammals, causing blood poisoning and even death, especially in sheep. Stable flies bite painfully, sucking blood from humans and animals. False stable flies do not bite, but spread certain diseases, whereas the little house fly hovers in mid-air in the middle of rooms.
Adults are about 1/6 to 1/4 inch long with reddish-brown eyes. Females are usually larger than males and have wider spacing between the eyes.
Bottle and Blow Flies
Blow flies, sometimes known as green or blue bottle flies, are larger than common house flies. Some are characterized by metallic colors such as black, blue and green or copper. Adults make a loud, droning buzz.
Black Garbage Fly
Adults are shiny black and about 2/3 the size of a house fly. Their life cycle is similar to the house fly.
Little House Fly
Adults are similar to house flies except they are smaller – 1/8 to 3/16 inch long.
Sanitation is the most effective and important step in controlling flies. All outside trash areas must be kept clean. Garbage should be drained and wrapped in plastic bags before being placed in trash receptacles or dumpsters outdoors. By placing garbage in bags, odors will be reduced, therefore attracting fewer egg-laying flies. (Reduce attractive odors by routinely scraping out and thoroughly cleaning food residues from garbage containers.)
Eliminate all potential breeding materials such as rotting straw or mulch, manure, garbage and animal excrement. Avoid damp pet foods left outdoors for several days. Eliminate carcasses of dead animals and birds. Any potential breeding material should be spread out thinly in the field and allowed to dry to prevent fly development.
Dispose of piles of old, wet, lawn clippings, leaves, manure stacks, old wet hay or straw bales and other such debris. Waste piles can be covered with black plastic which will heat the organic matter, destroying fly development.
At picnics and cookouts, keep foods covered and protected from flies until eaten. Remove fermenting overripe fruits from the ground. Flies may move several miles within a day or two, often originating from unsanitary sites.
Drain flies sometimes appear suddenly and mysteriously, becoming a nuisance in both homes and sewage disposal plants. Adult flies may become so numerous indoors that they congregate at windows, darken lamp shades at night, fall into food and accumulate around showers, bathtubs, sinks and floor drains, especially in the basement. Outdoors they mar fresh paint and plug sewage filter beds (intakes and drains), getting into the eyes, ears and nose of people in the area. Bronchial asthma can be caused by inhaling fragments and dust of dead flies. Since these flies originate in filthy conditions, there is the possibility of human health disease transmission.
Adult drain flies are tiny (5 to 6-mm long), fuzzy, dark or greyish insects with the body and wings densely covered with hairs. The antennae are long (13 segments), with each segment having a “bulbous swelling” with a whorl of long hairs. Wings, appearing too large for the body, are held roof-like over the body when at rest, giving a moth like appearance. Eggs are tiny, brown or cream-coloured and are laid in irregular masses of 10 to 200. Larvae are legless, about 9-mm long, worm like and grey, with both ends somewhat darker.
Life Cycle and Habits
Drain flies reproduce in polluted, shallow water or highly moist organic solids. The eggs, larvae and pupae can be found in the muck, slime, or gelatinous film often accumulating on the sides of drains and overflow pipes in homes, or in sewage disposal beds, septic tanks and moist compost. They have also been found in dirty garbage containers, rain barrels and tree holes.
Drain flies do not bite humans but may become a nuisance by their presence in large populations. Sometimes it takes persistent effort to eradicate an infestation in the home. Concentrate on eliminating larval breeding sites from drains in floors, sinks, wash basins, bathtubs, etc. Sometimes the source of the problem is a nearby filter plant.
MIDGES & CRANE FLIES
Non-biting midges are small 3-mm to 1.27-cm long, delicate, mosquito-like, but lack scales on their wings. Adults are humpbacked, brown, black, orange, or grey, lack a long beak, and males have very feathery antennae. Larvae are often whitish, cylindrical-like, elongate or worm like up to 1.27-cm to 1.9-cm long. Some are known as “bloodworms” or “red worms” due to the presence of hemoglobin in the blood. Others have a greenish color.
Biting midges are very tiny (less than 6.35-mm long), slender gnat-like flies. Some have narrow spotted or clear wings. Larvae are tiny, whitish, elongate, or wormlike, and are found in sand, mud, decaying vegetation, and water in tree holes.
Crane flies are small to large (4-mm to just under 2.5-cm long) long-legged and slender-bodied. Many have patterned wings and resemble mosquitoes. The larvae, called “leatherjackets,” develop a tough skin and can usually be found in damp soil feeding on decaying vegetable matter. Maggots are legless, have poorly developed heads, and are about 2.5-cm long when mature.
No control measures for midges are entirely satisfactory when large bodies of water are nearby. Locating the source of breeding is best. If possible and practical, locate standing water on your premises and eliminate it. Midges may fly as far as a quarter of a mile from the breeding site such as a lagoon, drainage ditch, standing water, lake or pond. They can also develop in and around buildings in well-watered soils and occasionally in standing water from air-conditioning units on building roofs. Check stagnant, polluted water accumulating in bird baths, clogged rain gutters, water-holding tree stumps, flower pots, old tires, etc.