Where Do Gnats Breed?

Fruit Fly Breeding Sites

Fruit flies breed and develop in places where foods such as fruits and vegetables are located and also where organic debris is allowed to accumulate. Common sources are fruits and vegetables that are aging, rotting or otherwise in a state of fermentation. Other commonly encountered development sites include moist areas that support accumulations of organic matter such as dirty drain lines, poorly cleaned garbage disposals and garbage cans, recycle containers or other places where “slime” inside other waste receptacles where organic debris is allowed to collect.

Kitchens, Bars & Restaurants

Other commonly encountered breeding and developmental sites of fruit flies include the cracks and crevices of kitchen equipment, crevices where floors and walls intersect and mops or brooms that contain food debris or other organic materials. In bars and restaurants, fruit flies are frequently found around the beer and soda dispensers. Often fruit flies may hitchhike inside a home or food service business on infested fruits and vegetables or fly inside through open doors and windows.

Keep Surfaces Dry & Sanitary

Since females lay eggs on the surface of fruit or the “slime” that occurs in their developmental sites, the key to preventing and controlling fruit flies is to maintain clean, dry and sanitary conditions. Not only are fruit flies a nuisance, they also may contaminate foods with bacteria and other organisms that can cause food-related diseases.

image of a gnat

Moth Fly Breeding Sites

Moth flies, also called drain flies, look like very small, hairy winged moths rather than typical flies. Their developmental sites are generally indoor and outdoor locations where moisture accumulates for about 7 or more days and there is a source of organic matter in the water. The typical habitat of drain flies is somewhat similar to fruit flies and includes drains, drain pipes, sinks and other places where a surface film of organic matter they use for food is allowed to accumulate.

Other Places to Check

One of the more likely habitats for drain fly development includes moisture that accumulates from broken sewer pipes that allow organic laden sewage to accumulate under the slabs and walls of homes and other buildings. Other sources are air conditioner and refrigerator condensation drains, and stopped up gutters.

Keep Drains Clean

The most effective control of drain flies is to eliminate their habitats by cleaning drains, sewer pipes and other sources that stay moist and other places where the organic matter slime accumulates, a task that is much easier said than done.

Phorid Flies

Phorid flies are also called humpbacked flies or scuttle flies and develop in an extremely wide variety of both plant and animal decaying materials. Examples of development sites are rotting plants, moist manure, carrion and the slimy mixture of moist organic matter that can accumulate in drains and plumbing.

Many Possible Breeding Grounds

Other sites where phorid flies are likely to develop are food residues in trash containers, poorly maintained garbage disposals, dirty mops, organic material on the bottom of pet cages, the bottom of elevator pits, sump pumps and sewage from broken sewer lines that leak onto soil.

Mausoleums, Bakeries, and Hospitals

These flies are also commonly found developing in the cracks of kitchen equipment and have even been known to infest mausoleums and feed on human corpses. Frequently found in bakeries, their sources of foods are damp, decaying flour that accumulates in and under equipment, plus cracks and gaps in floors and wall-floor junctions. Phorid flies are particularly problematic in hospitals and other health care facilities.

How to Identify Phorid Flies

Phorid flies have a peculiar behavior of preferring to run rather than fly when disturbed. This behavior, coupled and their humpbacked appearance are two characteristics to help identify these flies.

Fungus Gnats

Fungus gnat development sites are usually associated with plants and moist soil where they feed on damp, organic material and live in piles of plant debris, compost piles and mulch around the house. These flies feed on fungi as well as plant roots that are found in soil habitats. As expected, fungus gnats are problems in greenhouses and potted plants found inside homes.

Avoid Over-Watering Plants

Adequate moisture is the fungus gnats’ key to survival and more often than not simply replacing potting soil and watering plants less will resolve the problems created by fungus gnats.

How Do They Get Inside?

Fungus gnats may fly inside homes and other buildings from their outside development sites, or be directly brought inside on an infested plant. Fungus gnats are attracted to lights.