Phorid flies, also known as humpbacked flies, are small and 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. Color: Tan brown with black eyes; small head; a severely arched (humpbacked) thorax when viewed from the side.
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 common in homes and commercial facilities where food is prepared and served, but they are also a key pest in food warehouses, and hospitals. Because these flies frequent unsanitary conditions, they are a potential health concern when they occur in food facilities and hospitals. Phorid fly larvae have been found in the open wounds of patients in nursing homes and hospitals.
Phorid flies are capable in breeding in more types of materials than any other structure-infesting flies. 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. In nature, they are typically associated with dead animals and heavily decaying vegetation. In buildings, they be may found breeding in drains, trash containers, dumpsters, rotting produce, recycle bins, grease traps, garbage disposals, crawlspaces, and any site where moist organic matter can accumulate for a few days or longer.
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. If you locate a drain that is a breeding ground for Phorid flies, use a foaming drain cleaner 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.
Many pest professionals have foam generators that will fill drain pipes coating all surfaces for effective Phorid fly control.