Blow and Bottle Flies are found worldwide, occurring nearly every place inhabited by people. The name blow fly comes from the bloated condition of the rotting animal carcasses that their larvae, known as maggots, infest. Blow flies are one of the most common flies found around dead animals.
These flies are common in populated areas and are often found near meat-processing plants, garage dumps and slaughterhouses.
Blow Flies also include a number of species including the common bluebottle fly, Calliphora vomitoria (Linnaeus) the green bottlefly, Phaenicia sericata (Meigen) and others.
Blow flies are slightly larger than true house flies, and the bodies of many are metallic blue or green in color. Worldwide, there are about 1200 species of blow flies, and in North America there are 80. In many areas including the American Southwest, blow flies are the most common type of flies found in and around buildings. Blow flies range in length from 7 to 16 mm (0.28 to 0.63 in); they have robust bodies and wide heads.
1. Exclusion and Sanitation
- Locate and eliminate all possible breeding sources. Blow Flies and Bottle Flies feed and breed on dead animals and garbage. Whenever possible, remove all material where the flies can lay their eggs. Killing adult flies will reduce infestation, but elimination of breeding areas is necessary for proper management
- Proper sanitation measures must be taken with dumpsters and rodent control measures.
- Exclude Blow/Bottle Flies from a structure with proper screening and maintenance of doors and windows.
- Garbage cans and dumpsters should have tight-fitting lids and be cleaned regularly.
- Drainage will often aid control, getting rid of extra moisture.
- Openings of buildings should be tightly screened.
2. Using Insecticides, Fly Baits and Fly Traps
- Blow/Bottle Flies do not always require chemical control. However, if necessary, spray entry points on building or fly resting areas with residual liquid insecticides such as Cyper WSP or LambdaStar Ultra Cap 9.7. In order to maintain a residual control, use these insecticides once a month.
- Fly Glue Traps such as Best Sticky Glue Paper may be used to trap and kill Blow Flies. You can use the Sticky Fly Traps inside or outside.
- Fly Baits are a common method of fly control. If you use fly baits, remember to keep the fly bait as far away as possible from your house or building. Fly Bait such as Marlin Fly Bait, Bonanza Fly Bait or Maxforce Granular Fly Bait work quickly, killing flies in about 60 seconds, and keeps controlling them for up to 30 days.
- A pyrethrum aerosol will provide a contact kill for immediate relief. It may take a while for sanitation methods, residual chemical methods and fly baits to begin working. CB 80 Pyrethrin Aerosol or PT 565 can be used as a contact, quick kill insecticide.
Biology and Habits
Blow Flies, part of a large family of flies, is known for the larvae and immature flies infesting animal carcasses.
Adult blow flies feed primarily on flower nectar, plant sap, and other sugary materials. The female blow fly typically lays her eggs on the body of a recently killed animal. The eggs hatch quickly and the maggots then feed on the decaying tissues. In warm weather, some species can complete their larval growth within a week. They then burrow into the soil and pupate, to emerge later as adult flies. Blow flies play an essential role in nature by decomposing dead tissue in the wild.
Blow flies have played a role in medicine: species such as the green bottle fly and the black blow fly were once commonly used to clean open wounds in humans because the maggots tend to feed only on decayed tissue. Since blow flies routinely move between dead animals or dung and human habitats, they may transmit disease organisms to people, including the bacteria that cause dysentery, typhus, and cholera.
Blow Fly Inspection and Blow Fly Control
Eggs are usually laid on meat or dead animals. Some blow fly species, such as the screw worm fly, lay their eggs on living animals.
Most of these flies found indoors originate from an outside source because of their breeding preferences. Garbage cans are a huge source for blow flies. Single cans have produced more than 30,0000 flies in a week. If there are a large number of blow flies inside, it most likely is a sign of a dead rodent or bird somewhere in the structure. Finding the source of the animal or bird is often difficult because it has been dead several weeks by the time the flies appear.
If a dead animal odor is present, the odor may help narrow the search area. Look for signs of dead rodents or birds that may have been living in walls or crawl spaces, or even living in lower cabinets and under major appliances. Fly larvae will crawl along a wall until they encounter a corner where they then pupate. Numerous pupae in a corner indicate the breeding source is near. If the flies are found inside the light covers in the ceiling, it means the flies emerged either in the ceiling or from the wall. The breeding source might be either in the ceiling or a wall.
Outdoors, inspect the area for dead animals; any nearby dumpsters or other garbage containers should be inspected.