More than House Flies – Horse Flies!

Flies are part of life in the south. House flies are around almost twelve months of the year, for them we wield bright yellow fly-swatters. While annoying, we’ve learned to cope with their presence and behavior.

However, our warm humid weather encourages the appearance of another kind of fly that we don’t acknowledge with the same sang froid. This fly is a bigger, nastier, noisier relative of the house fly, commonly known as a horse fly. Sounding like a miniature fighter jet has invaded our living quarters, the horse fly (Tabanus sulcifrons) is making its annual appearance.

While the horse fly is not found in every location, there’s little doubt of its identity if it invades your space.

Varying in size from ½ to 1 ¼’’ long, usually gray or black, their eyes are often bright green, one of their identifying characteristics. If seen close up and immobile, another characteristic is apparent – its antennae are shorter than its head!

Not interested in the ‘close up and personal’ aspect of horse flies? Understandable, and incidentally horses do not have to be involved for horse flies to appear. These flies develop around streams, moist forest soils, and decomposing wood. Found in most areas of the U.S., the benefit of their 160+ species to the environment is consumption of decaying matter.

One of their less endearing attributes is the female’s need for a blood meal in order to lay eggs. To this end, females have mouthparts that resemble blades, used for slashing tissue and blood vessels to allow for flow, then employing a spongy mouthpart to suck up blood. Charming as the process sounds, the horse fly feeds on humans, in addition to horses, livestock, pets and birds.

Usually active during the day, they become problems if entering our homes, dive-bombing living organisms in a search for a meal or escape, perhaps depending on gender of the fly.

Female horse flies bite; remember they’re like mosquitoes searching for a blood meal. Bites can be painful, and can cause allergic reactions in some warm-blooded creatures. While horse flies are not normally associated with the transmission of diseases, they can vector them in humans and animals. If you or a pet exhibit persistent itching of area around a bite, or a rash on the body, a horse fly may be the culprit.

Getting rid of horse flies is not a simple activity since their developmental habitat is wide-spread and where insecticides offer at best short-term effectiveness. Of moderate help is the use of traps, of which there are several types. DIY (Do it Yourself) or traps purchased at one of several retail outlets, online searches offer several constructions and baits for traps, including the site shown.

Adult horse flies live about 30 days, we’re experiencing the height of their life cycle during our warm, wet, humid weather patterns.

They will disappear as suddenly as they appeared, in the meantime I’ve found a bright yellow fly-swatter works pretty well on them, too!

By Sallie Lee, Urban Regional Extension Agent, Alabama Cooperative Extension System.  Contact Sallie at

The Alabama Cooperative Extension System (ACES) operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities. ACES is committed to affirmative action, equal opportunity and the diversity of its workforce.  Educational programs of ACES serve all people regardless of race, color, age, sex, religion, disability, sexual orientation, or national origin.

Alabama Extension

The Alabama Cooperative Extension System operates as the primary outreach organization for the land-grant functions of Alabama A&M and Auburn Universities and answers home-gardeners' questions each week on Birmingham Gardening Today.

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