PHORID FLIES

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• Identification of Phorid Flies

• Phorid Fly Picture

• Phorid Fly Elimination

• Products for Fly Elimination

• Phorid Fly Biology

• Phorid Fly Life History

• Inspecting for Phorid Flies

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Identification of Phorid Flies

Phorid Fly Image

The phorids, also known as humpbacked flies, are small to minute flies that resemble fruit flies in appearance.  The Phorid fly lacks the red eye color that is the classic trademark of the fruit fly.  Phorid flies are in the small category of flies, measuring up to 1/8 inch in length, including the wings.  The most prominent feature of this fly is the humpbacked shape of its thorax.  The severe arch of the thorax gives it the common nickname of humpbacked fly.  The most easily recognized feature (seen with the naked eye) is the habit of the adult Phorid fly running rapidly across surfaces instead of immediately flying when disturbed.   Most flies immediately take flight. 

Phorid flies are also know as coffin flies, when found in mortuaries and mausoleums.

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Phorid Fly Elimination

The key to controlling phorid fly infestations is to locate and eliminate their breeding sources.  Although there are several sprays and traps used to kill flies in a home, restaurant or other structure, the infestation cannot be eliminated without eliminating their source.  A space spray (Pyrethrin aerosol) can be used as a quick kill, reducing populations of flying insects.  Pyrethrin aerosol is also a crack and crevice tool that is used to spray the tiny areas where Phorid Flies breed.  To monitor the area, use a Gold Stick trap.  These traps use a fly sex lure to attract flies to their doom.  Every Phorid fly caught is one less breeding, egg laying adult!  If you locate a drain that is a breeding ground for Phorid flies, use Drain Gel (formally called Fly Gel) to destroy the film in which the fly eggs and larvae are developing.  A surface spray is not recommended in this situation, unless there are great numbers of flies resting on the surface of trash cans, dumpsters or exterior walls.  Click here to see fly elimination products.  Inspecting the area for possible breeding sources is the key for Phorid fly elimination.

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Phorid Fly Biology

The phorid fly breeds primarily in and feeds on moist decaying organic matter.   Because it frequents unsanitary areas (with the ability to spread disease causing bacteria onto food products) this fly is of particular concern to hospitals, health care facilities and restaurants.

The reproductive potential of these flies is tremendous and very large numbers of them may appear in a short time.  Adult flies are strong fliers, having been known to travel as far as 6 miles within a 24 hour period.  Phorid flies are found throughout the world and are a serious pest when found in food producing, food handling or food serving facilities.  Health care facilities are another favorite target of this fly. Phorid fly larvae have been found in the open wounds of patients in nursing homes and hospitals.  Fermenting materials such as fruit, dirty garbage containers, rotten vegetables or slime in drains are just a few of their favorite breeding and feeding places.

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Phorid Fly Life History

Phorid flies develop by egg, larva, pupa and adult.  The female will lay about 20 eggs at a time  and will lay about 40 eggs in a 12 hour period.  Each adult female phorid will lay approximately 500 eggs.  The tiny eggs are deposited on or near the surface of decaying organic matter.    Larvae emerge in 24 hours and feed for 8 to 16 days.  The Phorid fly larvae then crawl to a drier spot to pupate.  The life cycle from egg to adult can be completed in as little as 14 days (under ideal conditions) but may take as long as 37 days to complete their cycle.

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Inspecting for Phorid Flies

Adult Phorid flies are fairly common in many habitats, but are most abundant about decaying plant and animal matter.  In structures, these flies can be found breeding wherever moisture exists around plumbing and drains in bathroom and kitchen areas, garbage containers, garbage disposals, crawl space areas and basements.  These breeding areas are occasionally very difficult to locate.  Although it is primarily used to reduce fly populations, a Gold Stick pheromone trap can be used to monitor different areas of the home.  This will help identify the areas populated with flies and help locate their possible breeding sites.

When searching for Phorid fly breeding sources, remember that the larva can only survive  in decaying organic matter that is moist.  The first obvious place to check is where any fruits or vegetables or stored outside of refrigerators or coolers.   Other areas to inspect would be recycling bins, seldom used (or cleaned) garbage cans, underneath and behind large appliances.  Do not overlook drains where small flies are often found breeding in the super thin layer or film of debris that naturally accumulates in pipes, traps and drains.

In commercial and residential structures, tiny amounts of organic debris are often found where the legs or feet of appliances, tables or cabinets touch the floor.   These tiny spaces can harbor thousands of fly larvae.  All small cracks and crevices at floor level need to be inspected and thoroughly cleaned.

Once one source has been located, continue with your inspection.  Phorid flies easily follow air currents and usually have several breeding places in any structure.  Do not assume that all of your breeding sources are indoors; fruit flies will wander in from nearby dumpsters, outdoor garbage cans or even damp compost piles where fruits and vegetables are disposed.

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