Get Rid of Phorid Flies

Phorid Fly (Humpback) Fly Control

phorid fly -humpback fly Both the Phorid fly and the Fruit fly are small flies. They come from two different fly families and are often are mistaken for each other. They are about 1/8 in long and somewhat similar looking, but their biology and management are very different. The drain fly/moth fly and the phorid flies are both common in drains. Understanding the different breeding sources for the different flies will help you in identifying and managing the respective flies. The other flies that are found around drains are: Fruit Flies, Drain Flies and Sphaerocierid Flies.


It is necessary to find the breeding sources of phorid fly infestations Finding these breeding sources is the difficult part but removing breeding sources is the only viable long term solution. This solution may include something as simple as throwing away a piece of rotting fruit found under the stove or cleaning a floor drain. The regular cleaning of floor drains crucial in preventing infestations of phorid flies and several other flies. Bleach and hot water WILL NOT eliminate fly larvae breeding in a drain. Use Invade Bio products instead to eat the organic matter instead of bleach.The film of organic matter which lines the drain is where the larvae live. This film must be removed to kill or remove the larvae. Remove this film by using a stiff drain brush and an industrial type drain cleaner. Water can then be used to flush the drain completely.

Cleaning infested drains initially is quite often a messy job, but future cleanings will be easier to complete.

If phorid flies are found to be breeding in the soil or gravel under a concrete slab floor, the only way to eliminate the infestation is to break a hole in the floor and completely remove the infested organic material. Repair all broken pipes, replace new soil or gravel, and fill gaps in the slab. This procedure is a difficult and often costly remedy to this situation. Drilling and treating the infested soil under the slab with residual insecticides does NOT work. This has been proven by countless experiences. The excess moisture may dilute insecticides or insulate the fly larvae from it. The insecticide may also not reach all areas where the fly larvae are developing. Decaying organic matter can also quickly break down insecticides making them ineffective. More important, no insecticide is labeled for such treatment. It is important to understand what is required and make the necessary corrections if you truly want total relief from these flies. When phorid flies are found to be breeding in organic matter trapped under the legs and bottom edges of equipment in kitchens, the organic debris must be removed. It is sometimes necessary to move or lift the piece of equipment to clean properly. The crack between the bottom of the portion of equipment and the floor must be thoroughly dried, and a long-lasting caulk applies to seal the crack. The caulk prevents water and food from re-entering the crack where it can again serve as a breeding source for flies. Once breeding sources have been removed, remaining adult flies will die off in a few days.

Sanitation Treatments

invade bio foaminvade hot spot Invade Bio Products- Use Invade Bio Products in the drains. A use of a drain cleaner such as Invade Bio Gel Treatment will remove the organic debris, improving santitation.


If the Phorid flies are breeding in the soil under a concrete slab, the only way to eliminate the infestation is to remove the contaminated soil by breaking through the slab and replacing the soil. Any broken pipes need repair. Drilling and treating the infested soil under the slab with residual insecticides does not work.

Remove all organic debris trapped in small cracks and crevices under the legs and bottom edges of kitchen equipment. The debris needs to remove, thoroughly dried and a long lasting caulk applied to seal the crack.

Invade Bio Foam is another another type of Invade Bio product; particularly useful in commercial establishments. It is a concentrated bio liquid with the use of a foamer. Invade Bio Foam contains concentrated scum-eating, odor eliminating microbes and foaming agent. Use this a part of an integrated pest management tool. Use 1 oz per quart, 4 oz per gallon. Apply using a B&G VersaFoamer HH or sprayer to cracks, crevices and drains where small flies breed. The foam and citrus combination will digest the organic debris present as part of pest management. Mix Ultra-concentrated InVade Bio Foam with water at a rate of 4 oz per gallon (1 oz per quart) and applied using Foam Sprayers.

Invade Hot Spot is a Microbial/Citrus Foam in an easy-to-use 16 oz aerosol. Hot Spot is an aerosol can that contains the same premium microbes and ingredients as InVade Bio Foam. The 360 degree valve allows for foam dispensing in any orientation to easily hit hard-to-reach areas.

Use Contact Aerosols (Pyrethrins)

After breeding sources have been removed a space spray such a pyrethrins, a non residual insecticide can be applied to kill the adult flies.

Use Fly Lights

Another tool you could use would be insect light traps, but they attract mostly male phorid flies. There use involved with this type of fly would be limited except as a tool for monitoring.


If adults do not disappear within a week further treatments or looking for other breeding sources is needed.

Inspection Tips for the Phorid Fly

  • Adult Phorid flies are fairly common in many habitats, but are most abundant about decaying plant and animal matter. When searching for Phorid fly breeding sources, remember that the larva can only survive in decaying organic matter that is moist.
  • In structures, Phorid 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.
  • When searching for the breeding sources of phorid flies, keep in mind that the larvae can survive only in moist, decaying organic matter. The first spot that should be checked are the floor drains, if any are present. Fly larvae live in the moist film that develops on the sides of a drain and in debris which may become trapped on the edge of the drain. The presence of numerous adult flies inside a drain is a good sign that the drain is a breeding site. Use a knife or screwdriver to scrape the film off the sides of the drain and examine it for live larvae.
  • Occasionally, drain pipes will break under slab floors, and Phorid flies can breed in immense numbers in the organic debris deposited through the break in the pipe under the slab.
  • To determine if Phorid flies are exiting through cracks in a floor or from a drain, place pieces of masking tape over the crack or the drain opening. Leave space between the strips of tape to allow air movement for the flies to follow. If flies are exiting the openings, some of them will become stuck to the tape.
  • Other areas to check are where any fruits or vegetables or stored outside of refrigerators or coolers. Also inspect recycling bins, garbage cans, and underneath refrigerators.
  • 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. Restaurants, bakeries and food processing facilities use water hoses to wash the floors. Water under pressure can force food debris and moisture into the cracks and crevices where it ferments and starts breeding sites.These breeding sites can harbor thousands of fly larvae. All small cracks and crevices at floor level need to be inspected and thoroughly cleaned. Use a small spatula or knife to scrape any debris from inside the cracks and crevices for inspection of live larvae.
  • These flies are not always breeding near where they are found. Because these flies can fly, the breeding source can be located in another area. Phorid flies easily follow air currents and usually have a lot of breeding places in any structure.
  • Trash containers, which are not cleaned regularly are another good source for Phorid flies.
  • Other sites where Phorid flies might be found include garbage disposals, rotting meat and vegetables, the overwatered soil of potted plants, and fresh flowers in vases. They have also been found breeding in dirty mops in janitor closets and laundry rooms, animal feces, faulty septic systems, and human cadavers.
  • Don't stop looking when one breeding source has been found. In most cases, several breeding sources will be present.
  • Phorid Fly Identification

    phorid fly -humpback fly

    The phorids, also known as humpbacked flies, are small flies that resemble Fruit Flies in appearance. They are usually tan to dark brown in color. 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. A key indentifying trait is that the adult Phorid fly has a distinctive habit of 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.

    Phorid flies have also been found to breed in poorly stored meats, damaged containers of moist foods, and organic-based glues and paints.


    Phorid Fly Biology and Habits

    Adults phorid flies are most active during the warmer months of the year but can be active during the winter months.

    The Phorid fly is common in many habitats, but are more abundant in decaying plant and animal matter.

    Phorid flies breed primarily in and feeds on the moist decaying organic matter. The phorid fly can be found breeding wherever moisture exists, such as around plumbing and drains in bathrooms and kitchen areas, garbage containers, crawl spaces, and basements.

    Because it frequents unsanitary areas (with the ability to spread disease-causing bacteria onto food products), this fly is of particular concern to hospitals, healthcare facilities, and restaurants. Open wounds of patients in healthcare facilities often house phorid fly larvae.

    The Phorid fly life cycle is egg, larvae, pupa, and adult. Phorid flies deposit eggs on or near surfaces of decaying organic matter. The female phorid fly will lay about 40 eggs over a 12 hour period. The larvae emerge and feed for several days, then crawl to a drier spot to pupate. The life cycle varies from 14 days to 37 days.