Equine Pests: The ‘Most Wanted’ List

When battling insects that irritate your horse, it helps to know your foes—many of which have wings. Here's a list of common equine pests compiled from Cooperative Extension reports around the United States.

Flies are just one insect horses must battle each summer.

Horse-flies, biting midges and mosquitoes are attacking horses across the United States. Don’t let the winged foes of summer feed off your horse—or worse, use them as an egg incubator. Fight back. The first rule of battle? Know your enemy. We’ve compiled this summer’s “most-wanted” list from cooperative extension reports across the country.


In this part of the country, non-biting face flies and houseflies feed on equine saliva, tears, mucous, sweat, and wounds. They look deceivingly similar and tend to cluster around the animals’ eyes, mouth, and muzzle. They lay eggs in manure, so clean stalls frequently.

Stable flies also resemble the common housefly but are slightly smaller in size. Adults take one bloodmeal per day and their bites are incredibly painful. All three can spread disease and/or parasites. Extra yuck: the face fly transmits eyeworms throughout North America.

Horse-flies, deer flies, black flies and horn flies exist here, too. The blood from their bites can attract houseflies. Black flies target the inside of equine ears but can also irritate the area between the head and the belly. Horn flies, common around cattle, hang off the bodies and legs of their hosts.

Biting midges/gnats can transmit worms and cause “sweet itch,” while mosquitoes are vectors for encephalitic viruses. Equine botflies buzz around, laying their eggs on horses’ forelegs, shoulders and lips that, if ingested, can cause digestive tract damage.


Stable and houseflies are frequent in this region, as are face flies, black flies, mosquitoes, biting midges/gnats, horse-flies and deer flies.

Equine botflies are another problem in the Midwest. They look like a scrawny honeybee and love the heat. Adult botflies lay eggs on horses’ inner legs, knees, chins, noses and bellies. Horses then ingest the eggs as they lick the infected areas. Monitor your horse and remove bot eggs before they have a chance to be internalized. Dewormers can also work wonders.

Horses pastured near cattle also attract horn flies and heel (or warble) flies. The latter typically deposit their eggs on the hind legs; the larvae bore into the skin and travel through the horse’s system.


Mosquitoes, stable flies, horse-flies and gnats, as well as horn flies, deer flies, houseflies, and heel flies commonly annoy horses in the South. Other common tormentors include midges and moth-like sand flies (tiny, bloodsucking disease vectors that are active at night).

Although the black fly is less prevalent here, the equine botfly can be active year round. The face fly is also found in some Southern locales. Eye gnats are known irritants, gravitating to blood, mucous and sebaceous secretions. Blow flies are seasonal, laying eggs in wounds, but screwworm flies have largely been eradicated.


Insects that pester horses in the Western states include mosquitoes, biting gnats, black flies, houseflies, and face flies. Deer flies and horse-flies also abound here in the summer. Equine botflies (including the “nose fly”) pose another challenge. There have also been reports of eye gnats in southern California.

Gear Up For Battle

Good stable management is critical to fending off these disease vectors. Clean your horse stalls daily, eliminate any standing water,, and keep food securely stored.

You’ll also want to add physical protection to your fly control program, says Pamela Thomas Graham of the United States Equine Rescue League.

Protect your horse from insects with Cashel Company’s fly protection.

“We use fly masks for the rescues and fosters, because some of them have sensitivity to light or may have carcinoma—and, of course, for the general purpose of protecting the eyes from flies and protecting against sunburn,” she said.

One style on the market, Cashel’s Crusader Fly Mask, not only protects the eyes and face, but blocks 70% of harmful UV rays and guards against forelock damage.

Get ready. The summer bug battle has just begun.

Safe, durable and affordable. No matter the insect, Cashel has a solution for you. www.cashelcompany.com

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