Protecting Horses From Horse and Deer Fly Bites

commercially available horse and deer fly traps use the vision of these flies to maximize attraction and trapping Wall and Doane 1980 Watson et al. 2007 Kline et al. 2018 Figure 4. Three types of traps are available for horse and deer flies 1 the Horse Pal trap and the Bitelite HTrap which use a suspended black ball 2 the Epps Biting Fly Trap which uses a large darkcolored sheet and 3 box traps that are stationary darkcolored areas.
The Horse Pal trap uses a suspended black ball to mimic an animal. The ball is covered with a canopy that encourages the natural upward flight of flies attracted to the swaying ball. Flies are trapped in a clear jar at the top of the canopy. The principle is similar for the BiteLite HTrap. The Horse Pal trap has four legs while the BiteLite HTrap is a single post.
The Epps Biting Fly Trap uses a large darkcolored tarp that may resemble a large animal. Instead of trapping flies the Epps Biting Fly Trap deflects flies that land on the panels into trays of soapy water where they will drown. This trap requires regular maintenance to remove flies from the trays often so that new captures cannot use previously caught flies to escape.
Box traps have an open bottom mounted on four legs. The top of the box is covered with screening. Flies enter the underside of the box and are channeled upward by screens to the upper part of the box where they die. A commercial box trap the FlyCatchR is available. These traps are typically used for horse and deer fly capture in salt marsh areas.
The most important component of trapping horse and deer flies is trap placement. Horses and other animals should not be able to interfere with traps. However traps
should be placed where flies are a problem. These traps are especially useful in areas where horses cannot escape bites such as in small pastures or near riding arenas. Traps should be in sunny areas where they can be seen from the woods or marshy areas and away from buildings or other obstructions that might interfere with fly vision. Sometimes effective placement requires a bit of trial and error. If traps are not successful initially moving them just a few yards can increase trap captures. It is estimated that a trap can cover about 2 acres if properly placed.

Other traps for nuisance flies such as jug traps scatter baits and other visual targets like BiteFree sticky traps for stable flies will not be effective for horse and deer fly control.
OnHorse Fly Protection
Fly sheets boots and masks are barriers that protect horses from multiple species of biting flies like stable flies horn flies and horse and deer flies. While there are several options available to individualize fit and comfort zebra patterns in particular decrease fly attacks because of how horse and deer flies perceive color Caro et al. 2019 Figure 5.

Fly Repellents
Fullbody application of repellent products with synthetic pyrethroids seems to be effective. Horse and deer flies will bite any area of the body so it is important to have fullcoverage application. Better coverage can be achieved by applying repellent to a brush or microfiber mitt or similar and then applying to the horse Figure 6. While likely to be deterred from landing on a horse horse and deer flies may still repeatedly fly around a horse even after application and land on the legs or belly areas as the repellent loses effectiveness. Frequent reapplication is likely necessary at least daily or before riding in areas where horse and deer flies
are present.
Caution Pesticides Are Poisonous
Be sure to fully read and understand pesticide labels and Safety Data Sheets before applying any pest control product on the farm. Handle pesticides carefully and store them in their original labeled containers out of the reach of children pets and other animals. Dispose of empty containers right away in a safe manner and place. Do not contaminate forage streams or ponds.
Conclusion
Horse and deer flies are both a nuisance and a vector for serious equine diseases. Control of these flies is more difficult than stable flies or other pest flies. Altering turnout and pasture management may help and traps have been shown to be effective. Fly sheets and fly sprays can be used to help reduce bites.