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Small Biting Flies

Biting Fly Control: Protect Your Home or Business


  • There are many different types of biting flies, but black flies and midges are the two most common indoor pests.
  • Female flies are the main source of bites because they require blood meals to produce eggs.
  • The majority of biting flies use the carbon dioxide exhaled by people and animals to find their targets.


Appearances widely vary, but most biting flies have large compound eyes, antennae, and a pair of transparent wings. At a half-inch long, black flies are smaller than horse or deer flies. Their larvae have a dark brown or cream hue, and they develop in flowing water such as rivers and streams.

Biting gnats are about the size of a pencil tip. Biting midges, or no-see-ums, get the name due to their tiny, translucent bodies, which make the pests hard to spot. Their white, worm-like larvae grow to around a quarter inch in length.

How Do Biting Flies Get Inside Buildings?

Most biting flies avoid homes, as they prefer natural habitats. However, biting midges and black flies may invade properties near canals or marshes to find a meal. Both can get in houses through open doors or vents leading inside. Midges are also small enough to fit through mesh screens. Horse, deer, and stable flies will bite you outside but rarely enter buildings.

Busy commercial areas that produce carbon dioxide via machinery or people are major attractants. Open bays in warehouses and manufacturing plants also invite the insects inside. Overwatered lawns with poor drainage near university and office buildings create breeding sites for certain kinds of biting flies as well.

Signs of a Biting Fly Infestation

Since biting flies need moist soil and moving waterways to lay their eggs, having a property close to either one is an early indicator of potential issues. A few signs of a serious biting fly infestation in your home or business are:

  • Bites – Swollen, itchy red spots develop where biting flies take blood meals. Since no-see-ums are difficult to observe, this may be the only symptom you encounter.
  • Swarms – Flies often congregate in groups. Black flies in particular travel in large numbers after emerging from rivers in search of meals.
  • Noise – The insects’ buzzing sound is a nuisance at night and during the day.

Problems Caused by Biting Flies

These pests take blood meals from both humans and animals. Their bites leave skin swollen, itchy, and red. Scratching the inflamed bumps can also lead to infection. In more severe cases, people may experience allergic reactions to fly saliva and need immediate medical attention.

Businesses along water sources are at a higher risk for biting fly problems. Restaurants with outdoor patios may see patrons accosted by swarms of black flies or midges, risking both sales and profits. Hotels by popular nature sites may suffer damaging guest reviews, as well.

Prevention Tips

Installing insect-proof mesh in porch windows or patio screens will repel pests such as biting midges and black flies. Midges are weak fliers, so box or ceiling fans help keep them out, too. Since biting flies lay eggs in moist environments, empty birdbaths, clean out gutters, and don’t overwater yards.

To prevent bites, cover as much of your skin as possible. Wear long-sleeve shirts and jeans in bright colors because the insects favor dark clothing. Repellents get rid of midges, but they won’t work against black, deer, and horse flies. Biting fly infestations are tough to handle alone. Reach out to our Western Pest Services experts to find the best route for control.

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