Gnats, Fruit Flies, and Humpback Flies Fact Sheet

The below information was provided by Brody Pest Control



Fungus gnats are small, dark flies most often found collecting around windows during fall and winter. Fungus gnats can be found indoors infesting potting mixes used for houseplants or hopping across the soil surface. High organic matter plant mixtures and organic fertilizers, such as fish emulsion, encourage fungus gnat development.

Overwatering, a common problem during fall and winter, increases fungi and fungus gnat development. Fungus gnats can reproduce on indoor plants and cause little if any damage. They also occur outdoors where they breed in mushrooms and other decaying plant materials.

Pomace or Fruit Fly

Pomace or fruit flies are among the smallest flies found in homes. They usually are light brown and may be marked with bright red eyes. These small “fruit flies” most often are found hovering around overly ripe fruit. Fermenting materials, such as leftover beer or soft drinks, also are a favorite food. Populations tend to be greatest in late summer and early fall as they infest fruits during the harvest season.

Drain Fly

Drain flies, also known as moth flies, are occasional problems in homes. These small, moth-like flies sometimes emerge from drains of sinks, particularly in spring. Drain fly maggots develop by feeding on bacteria and organic materials that can colonize the linings of drains. Large numbers of the flies can be produced where there is a problem with broken or leaking drain pipes.

Tips to Control Flies in Home
  • Clean areas where food residues may accumulate. Key locations include around kitchen equipment and fixtures and countertops that have a gap in between them. A steam cleaner may facilitate the cleaning process.
  • Repair plumbing leaks promptly to prevent water accumulation.
  • Clean up food and drink spills immediately.
  • Rinse all beverage containers prior to placement in lined recycle bins. Do not store recycled containers for more than seven days.
  • Inspect incoming fruit and vegetables for the presence of fruit flies. Over-ripe produce is most suspect and may be harboring eggs and larvae even if adults are not evident.
  • Store fruit and vegetables in plastic bins in a cool storage room.
  • Use trash bags for waste containers; empty and clean these bins weekly.
  • Clean drains/traps and strainers at least twice per week to eliminate residues that encourage fly development.
  • Place exterior trash cans, recycle bins and dumpsters away from building entrances.
  • Use non-toxic fruit fly traps to capture adult fruit flies.
  • Avoid overwatering potted plants; allow soil to dry between watering to prevent fungus gnat breeding.
  • Use yellow sticky traps placed on a stake in plant pots to capture adult fungus gnats.