Weekend Wellness: 7 Fly Control Tips

There’s no doubt about it — warmer weather has arrived in the Northern Hemisphere, which means flies have hatched and are ready and willing to bug the living crap out of our horses. Here are seven fly control tips to keep your horses happy and healthy.


It’s a nice, sunny day that is perfect for a ride with your horse. You sink into the saddle in pure relaxation. Then suddenly, a horse fly lands on your horse’s rear end. He swishes his tail and the tranquility of just moments ago is halted as your horse bucks mid-air to rid the biting pest. Can you relate? Most of us with horses – admittedly – can.

“Summer days provide the perfect environment for a rapid increase in fly populations. When flies are abundant, horses become irritated and stressed. More than that, flies cause far greater damage than being a nuisance alone,” warns Arnold Nagely, DVM, co-founder of Valley Vet Supply. “Flies also contribute to significant equine diseases and conditions. By controlling the fly population through a multi-pronged approach, horse owners can reduce risks for a number of health challenges, such as strangles, influenza, eye worms and summer sores.”

With risks heightening as temperatures climb and fly environments thrive, summer sores can have a painstaking impact on equine health and comfort. While curing them can be a relentless battle, preventing them begins simply—by controlling the fly population.

Summer sores are caused by house flies, face flies and stable flies, as they transfer parasitic nematode larvae (Habronema species) to moist areas around a horse’s open wounds, eyes, nostrils, mouth and genitalia. When the larvae create a hypersensitivity reaction, chronic, fleshy and non-healing wounds can result, known as summer sores. The condition is costly and can require months off from riding and training as the infected horse heals.

Anne-Marie Morgan is a horse owner and trainer. She’s no stranger to the negative impact flies can have on a horse, especially relating to summer sores. “Thankfully, we have a very clean barn with a great fly spray system that keeps flies, and the risks they present, to a minimum,” Morgan said.

Florida-based horse owner, Miriam Wohlers, also shared how, “In the summertime, it is a constant battle with summer sores. Flies are horrendous, due to the constant humidity. All you can do is work to contain the flies.”

Flies can be relentless, especially during the summer months.

Dr. Nagely said, “Horsemen likely have seen a rise in flies since April, and they can expect to see increased fly populations through September, even into October in some regions of the country. It’s best to begin fly control strategies as early in the season as possible to curb the numbers, reduce horse health risks and keep horses comfortable overall.”

Reduce the fly population at your horse barn with these seven simple strategies:


  • Insect growth regulators pass through the manure of treated horses, preventing flies from developing into adults by inhibiting the development of the exoskeleton in fly larvae.
  • Barn managers also have success in eliminating the fly population using fly predators, which are beneficial bugs that conquer the fly’s cocoon and kill immature pest flies naturally.


  • Regular cleanings help rid fly-attracting odors and the warm, moist environment that is a fly haven for laying eggs and source of food.
  • Help manage moist, wet areas of pastures through drainage where practical.
  • Remove manure piles off-site from pastures, or spread manure over fields and paddocks, to help dry out piles and attract fewer flies.
  • Spread out or remove uneaten hay to dry quickly.
  • Keep overburden of plant residue at a minimum by controlling and cutting back excessive weeds and plant growth.


  • From sticky traps to fly-attractant bags that can catch up to 40,000 flies, there are many options available.
  • Be sure to read the product label and directions, as it’s not uncommon to see these fly-attractant products hanging in areas in which horse owners would ideally want fewer flies. Be sure to pull flies away from the barn, not encourage more flies to come in.


  • Remove dropped grain and supplements from stalls and feed rooms; doing so also will help prevent visits from opportunistic rodents, and the snakes that might be right behind them.
  • Place tight-fitting lids on all garbage cans to stop flies from enjoying an all-you-can-eat buffet, plus prevent wafting, unpleasant aromas with regular cleanings.
  • Empty and scrub feed tubs and water buckets regularly to help keep flies at bay, as well as ensure horses have access to fresh, clean water at all times (a horse consumes an average of 10 gallons of fresh water per day.)


  • Using a premise spray quickly controls adult flies and other barn-residing insects, as well as helps deter new ones from entering the area.
  • Barn insecticide spray kits can offer reliable fly control measures, through automatically timed spray applications.
  • Fly spray is a must for quick and easy on-horse protection against flies. For the best results, make sure your horse is clean, so the spray sticks to the hair, not to dirt or mud.
  • Ensure the horse’s face is shielded from flies, too, by using a fly control product that is safe to use nearby their eyes. There are specially formulated ointments
  • that can be applied using a cloth for this sensitive area.


  • Fly apparel — such as fly sheets, masks and fly boots — also offers more protection than from a fly’s painful bite alone. Fly gear can provide UV protection for horses, with some sheets and masks blocking more than 80% of harmful UV rays.


  • Circulating air helps to deter flies because the air requires more work and energy from flies to travel to and land on your horse.

To help shield her mare from flies and Florida heat, Wohlers has three fans mounted and running in her mare’s stall at all times during warmer months. Coupled with using fly spray, she also regularly washes and switches out five fly masks, and uses fly traps. “I want my mare to be happy and healthy,” Wohlers said. “Flies are not only annoying, but they also carry a lot of diseases, and I don’t want her to contract anything from them. Flies can be so frustrating for her, and I want to do everything I possibly can to prevent them.”

This piece was published courtesy of Valley Vet Supply. Valley Vet Supply was founded in 1985 by veterinarians to provide customers with the very best animal health solutions. Building on over half a century of experience in veterinary medicine, Valley Vet Supply serves equine, pet and livestock owners with thousands of products and medications hand-selected by Valley Vet Supply founding veterinarians and their professional staff. With an in-house pharmacy that is licensed in all 50 states, and verified through the National Association of Boards of Pharmacy (NABP), Valley Vet Supply is the dedicated source for all things horse, livestock and pet. For more information, please visit ValleyVet.com.