Flies are a nuisance for any horse owner. Despite their small stature, these winged insects create havoc throughout the barn, pasture, and home. Some have painful bites that turn into ugly welts. Others can transmit potentially dangerous diseases. All have a tenacity that can frazzle even the calmest horse or most seasoned equine aficionado. But effective fly control doesn’t have to be difficult. In fact, control of horse, horn, stable, house, face, deer, and bot flies is simpler than you may realize.
target the culprit
There are approximately 120,000 different species of true flies throughout the world. Thankfully, only a small portion of these are troublesome for your horse. But no two fly species are identical. In fact, an insect control product that kills one species of fly may have no effect on another. Therefore, the key to effective fly control hinges on knowing which type of fly afflicts your horse. Then you can choose repellents, traps, and fly masks and sheets to better protect your horse.
types of flies
Horses are affected by seven basic species of flies. For the most part, each fly species attacks a different part of your horse’s body. Therefore, it is fairly easy to determine which type of fly is bothering your horse, based on the following criteria:
Defined: The horse bot fly lays its eggs (or nits) on your horse’s coat where they then remain attached to the hair. These eggs are consumed when your horse licks the afflicted area. After ingestion, the eggs mature into parasitic larvae and attach to your horse’s stomach lining. The larvae (or bots) can cause gastrointestinal disturbances. Adult bot flies have a hairy thorax, which is the region directly behind the head to which the wings are attached.
Control: Treat your horse with ivermectin-based dewormers labeled specifically for bot control. Pyrethrin- or permethrin-based fly repellents may help repel adult flies. Adult bot flies do not bite, but they can be a real nuisance to your horse. Remove any eggs you see with a bot knife.
Defined: Similar to, but smaller than, horse flies, deer flies have colored eyes and dark bands across their wings. They have a painful bite that can cause extreme and immediate pain to your horse. These vicious bites can also become infected in certain instances. Deer flies can transmit certain diseases, such as equine infectious anemia.
Control: Protect your horse with suitable fly ointment, wipe-on, or spray repellents. Set fly traps around your barn and pasture. Drain puddles and fill in areas around water tanks to reduce breeding sites. If possible, pasture your horse in a non-wooded, open and breezy area to help reduce exposure. Deer flies avoid deep shade and barns, so offering a shelter may help. Deer flies are also active during the day, so offering pasture at night versus during daylight hours can help reduce exposure.
Defined: Face flies are most common around cattle; however, horses stabled or pastured near cattle are also often afflicted. They feed on the secretions around the face. They resemble house flies, with a thorax that is gray with four dark stripes. A female’s abdomen is black with an orange base. A male has an orange-brown abdomen with a black base. The face fly does not bite, but can transfer certain diseases and parasites from one horse to another.
Control: If possible, pasture your horse away from cattle or stable your horse during the daytime. Use fly repellents and suitable fly masks to help protect your horse. In addition, frequent grooming can help clean away any facial secretions.
Defined: Horn flies are more slender and smaller than the common house fly. They have a brownish-gray or black body with a slight yellowish cast, brownish-red antennae, and smoky-tinged wings. There is also a pair of parallel stripes just behind the head. These blood-sucking flies are most common on horses pastured around infested cattle.
Control: If possible, pasture your horse away from cattle. Use fly repellents and perimeter sprays to deter these insects. A suitable fly mask and sheet can also offer protection.
Defined: Among the world’s largest flies, horse flies measure up to 1-1/4" long. They have a painful bite that can cause extreme and immediate pain to your horse. These vicious bites can also become infected in certain instances. These flies can also transmit diseases, such as equine infectious anemia. Horse flies also consume a large amount of blood when they bite. In large numbers, they could cause anemia.
Control: Protect your horse with suitable fly ointment, wipe-on, or spray repellents. Set fly traps around your barn and pasture. Drain puddles and fill in areas around water tanks to reduce breeding sites. If possible, pasture your horse in a non-wooded, open and breezy area to help reduce exposure. Horse flies avoid deep shade and barns, so offering a shelter may help. Horse flies are also active during the day, so offering pasture at night versus during daylight hours can help reduce exposure.
Defined: One of the most common flies, the house fly has a gray thorax with four dark lines. The abdomen underside is yellow. The entire body is covered with hair. Their eyes are red. House flies lay their eggs in manure and seek mucous secretions and wounds on your horse.
Control: Set fly traps throughout your barn and pasture. Use spray, wipe-on, and other repellents, as well as perimeter sprays, to help protect your horse. Frequently muck your stalls, barn walkways, paddocks, and harrow manure in the pasture with a suitable manure fork.
Defined: The stable fly is 1/4" long with a pale spot behind the head, a striped thorax, and seven dark spots on the abdomen. Stable flies are similar to the house fly in size and appearance. However, stable flies can transmit certain diseases, such as equine infectious anemia. These common biting flies typically feed on your horse’s lower legs. Horses generally stomp their feet in reaction to the bites. Both males and females feed on a horse’s blood supply. Stable flies lay their eggs in manure, wet straw, and grass clippings.
Control: Set fly traps throughout your barn and pasture. Pyrethrin- or permethrin-based fly repellents can help kill and repel. In addition, remove old compost, hay, and manure to reduce breeding sites.
total fly control
Fly control can seem like a daunting task. However, by targeting the specific flies that are attacking your horse, you can better help protect your horse. In addition, you can use total insect control techniques to help reduce the breeding sites around your barn and pasture and repel further fly infestations.
Contributed By: Drs. Foster & Smith Educational Staff