Domestic Flies

Life Cycle



The female lays very small white eggs, usually about one millimetre in length. These are deposited in or near damp locations since they are susceptible to drying. This coupled with the females’ ability to lay thousands of eggs give these pests tremendous reproductive capabilities.


The egg will usually hatch within a day, and the larvae will live in moist organic matter until ready to pupate.


The cast pupal cases are clues to the breeding place. It is usually necessary to look at the adult for identification characteristics, since there are very few clues available for identification based on the larvae or pupa.


When the fly emerges from the pupal case, it is full size. It emerges as an adult and will not increase in size. For a short time after emergence, it is unable to fly and is referred to as a “crawler”. Most domestic flies have similar life cycles. The developmental period is relatively short when compared with that of other insects.

House Flies All dull grey flies found inside or even near structures will likely be called house flies.

The house fly, (Musca domestica) that lives on garbage or manure, and its close relative, *The face fly (Musca autumnalis) that lives on fresh cattle manure, are about 0.6 cm (1/4 inch) long. They have a dull grey thorax with dark stripes and a dull abdomen with yellow sides.

Flesh flies (the family Sarcophagidae) live on meat scraps, dead animals, and dog excrement. They are more than 0.6 cm (1/4 inch) long. They have a dull, grey thorax with three distinct dark stripes and a grey checkerboard abdomen.

Blow flies (the family Calliphoridac) are about 0.6 cm (1/4inch) long. Their thorax and abdomen are shiny black, metallic green or bronze, or they have a metallic blue abdomen with a dull thorax. They live on dead animals, meat scraps in garbage, and wet mixed garbage.

The cluster fly (Pollenia rudis) is also in the family Calliphoridae. It is slightly more than 0.6 cm (1/4 inch) long. Its thorax is covered with grey or yellowish hairs; it has nostripes. Its abdomen is dark grey with light patches.



When any of these flies become problems inside, their breeding site and larvae will usually be close by. If animals are nearby, investigate for manure concentrations. Garbage cans and dumpsters are often the problem source; even soil where garbage has composted will support infestations.

House flies infest most garbage, manure (horse, cattle, poultry, pet) and filth accumulations.

Face flies need fresh cattle manure for egg laying.

Flesh flies , like blow flies, live in pet manure, meat scraps in garbage, and dead animals.

The blow flies are scavengers and live in manure, dead birds, and rodents in wall voids and chimneys. One blow fly.

the cluster fly parasitizes earthworms. It is very important to look for fly sources in buildings that are infested. Garbage collection areas are the main area of concern. Proper sanitation methods must be adopted.

The most common means of fly entry is through open doors. Look for door props, and hooks, as well as gaps where broom handles are stuck over hinges to hold the door open.

The professional applicator during any pest management inspection must evaluate garbage disposal. Garbage that is left in the building or on loading docks is an attractant. Garbage should be removed from the premises twice a week. In favourable weather, house fly larvae mature in 6-10 days and blow files in 3-9 days. They live in refuse only from the egg laying to the mature larval stage. Then the mature larvae crawl away to pupate, emerging as adults later.

Habitat Alteration


Caulk and tighten around all openings such as screens, doors, windows, ventilators, and eves. The professional applicator must emphasize sanitation to the client. If sanitation cannot be improved, other methods of control will not be effective. It is important to conduct the following

  • Remove breeding materials such as garbage and manure.
  • Clean garbage cans and dumpsters regularly.
  • Clean food delivery spills immediately.
  • Drain wet areas around garbage collection sites.
  • Keep loading docks clean.
  • Install air curtains where doors remain open for deliveries, etc.
  • Install automatic door closes.
  • Replace white security lights inside and outside with yellow lights.

Pesticide Applications


  • Fly strips can be placed in low access rooms, such as attics and storerooms.
  • Fly bait can eliminate adult flies when methods are in place that reduce breeding sites.
  • Electric fly traps will control only a low level of adult flies. Monitor these traps to see what types of flies are being caught.
  • Do not place ultraviolet light traps where they will attract insects from outside; do not put them in competition with other lights such as those from vending machines.
  • Aerosol contact sprays can be used to knock down adult flies – after elimination of breeding sites and exclusion methods are in effect.
  • Ultra-low dosage applications of non-residual pesticides can be used if an adult infestation must be quickly reduced outside.
  • Use liquid pressurized sprays or dusts where flies have collected in wall voids. Likewise, treat around window and door frames and other cracks and crevices.
  • Hang sticky fly strips in front of attic windows, especially east windows.
  • Apply residual pesticides labelled for fly control to surfaces where flies rest, provided those surfaces are not used by people
  • The professional applicator must conduct a follow-up inspection to ensure sanitation and exclusion methods are being properly maintained.
  • Observe client and worker habits that run counter to the pest management program (sanitation, habitat alteration, and so forth).