Humpbacked Flies (Drain Flies)

Brian Prystups PHD

Humpbacked flies are also known as Phorid or Drain or scuttle flies. They get the name scuttle fly from their habit of running about in an active, erratic manner. They are fast fliers.

They can be serious indoor pests for retail stores, homes, hospitals , the hospitality & food industry. They are common in many habitats, but are most abundant around moist, decaying, organic matter including plants and animal material and especially drains and  transport disease organisms from their breeding locations.

In retail stores, Humpback flies are usually brought into stores on fruits and vegetables. Where possible inspect and approve suppliers ensuring pest prevention program in place at supplier

LIFE CYCLE

Common breeding sites, where larvae (immature forms or maggots) develop can be extremely diverse.

These areas include the organic film that can develop in drain pipes, the bottoms of trash cans, under kitchen equipment, on aging fruit, in broken sewage pipes and in potted plants or vases with flowers.

Developmental time varies, but the life cycle for most humpbacked flies (from egg to adult) is approximately two to four weeks.

NON-PESTICIDAL CONTROL

The first step to non-chemical control is to find areas where adult humpbacked flies lay their eggs and the larvae develop.

Good sanitation can be used for long-term control. Cleaning any moist, organic areas especially drains, with appropriate cleaners and a stiff brush to remove any organic biofilm should be effective. Also, hidden areas under kitchen equipment and sinks where moist, organic debris can accumulate should be cleaned. If these measures do not help, a plumber may be needed to check for hidden cracks and leaks in plumbing lines.

However, the best long-term control methods are basic hygiene, strong detergent solution (LIFT in strong concentration of 1 part LIFT to 10 parts WATER) followed after 10 minutes by BLEACH (Sodium Hypochlorite) solutions used to treat the drains. Pour solutions around the edge of drains to coat all sides of the drainpipes to dry out the organic matter and slime that supports the eggs and larvae.

•    The use of UV light units with Sticky insect control surfaces will drastically reduce the fly population and help prevent fly contamination of food & food contact surfaces.

( Click on picture to enlarge)  Thousands of Humpack Flies & some house flies trapped on a glue cartridge ( from an Ultra Inn Decorative wall mounted unit)	Paraclipse Terminator ( Ceiling Hung) double sided	Paraclipse Ultra Inn II (Wall mounted)

•    Trash should be kept covered and removed often.

Note: Humpbacked flies are small and can look like other types of flies. In addition, you can have multiple types of flies in your site at one time. Consider that you may have several areas where flies are breeding or different means by which they have been brought into your site. Inspect all moist, organic areas that can serve as a common breeding site.

Although there may be no overnight solution, with a thorough inspection and sanitation, control can be achieved.