Black Fly Facts & Information


What do they look like?

Black Fly Illustration Black Fly Illustration

How Did I Get Black Flies?

Black flies are biting pests that swarm humans and livestock. Homeowners living near waterways may have problems with black fly swarms on their property. Although these pests can accidentally get indoors, they do not infest, breed, or develop inside homes.

How Serious Are Black Flies?

While the pests are not a threat to homes, they are a menace for those who enjoy the outdoors. Black flies can make spending time in the backyard, park, or campground intolerable. These persistent insects crowd around the head, hair, and ears of their targets in search of a blood meal.

Black Fly Bites

Bites are painful and often result in severe lymph node swelling and skin rash. The insects cut into the skin to lap up blood that pools in the bite wound. Strong allergic reactions sometimes result from a bite.


Black fly swarms are unpleasant, but the pests don't spread any known human diseases known to be transmitted by black flies within the United States.

How Do I Get Rid of Black Flies?

Your local Orkin technician is trained to help manage black flies and similar pests. Since every building or home is different, your Orkin technician will design a unique program for your situation.

Orkin can provide the right solution to keep black flies in their place...out of your home, or business.



These insects have proven to be such a nuisance in summer months that special hiking gear has been developed to combat them. Research also shows that black flies are more attracted to dark colors than to light colors; hikers who dress accordingly are less likely to be bothered.

In order to avoid being bothered by black flies, hikers often tightly tuck in their shirts and pants.

Behavior, Diet & Habits

Where Do They Live?

These insects breed in flowing water, like streams, and rivers. Adults seek moist environments. Black flies are common in humid, wooded regions in summer months and can be found throughout semitropical regions year round.

Black flies are most active around sunset during June and July and act as severe nuisances to backpackers, hikers and other outdoor enthusiasts. Black flies are not active at night.