08/07/2026
After 55+ years of living with horses in several different climates & locations in the world, I have discovered a few things about dealing with flies! Unfortunately, there is no “magic spray” or silver bullet, but there is hope! Remember “flies” in general have a 15 - 45 day life cycle, so getting a handle on them takes a little time and diligence. If you have close neighbors who do not manage their flies well, your efforts will not be as successful.
Fly control falls into two categories:
1. Reduce fly population
2. Protect the horse from the rest of the flies
Ideally, we should prepare before fly season starts. First examine your stable area, loafing shed, paddocks, etc and improve the drainage and footing. Mow, trim, weed-eat vegetation and eliminate any possibility of standing water. Insects love moisture and filth! If you want to use fly traps, containers with attractant to catch flies, place them well away from the horses! Spray your structures with a concentrated knock down spray, the kind you can mix more strongly depending upon the application.
A month or so before fly season, start your horse on a fly control product designed to make him less attractive to flies. Beneficial ingredients are garlic, apple cider vinegar, brewers yeast, B vitamins. Other feed thru products contains chemicals to prevent the fly larvae from hatching in the manure, breaking the life cycle. Fly predators are beneficial insects that eat any fly larvae before they hatch. These are all the most beneficial if started before fly season!
Consider your manure disposal. Stalls, runs, loafing sheds should be cleaned at least daily, more often if you can. Put manure in covered receptacles or compost pile it as far away from the barn as possible. Consider fans in areas where horses hang out. The air movement makes flight more difficult for insects and disperses your horse’s scent, making him harder to find.
Most insect pests use odor to find your horse (or you!) so bathing with an enzymatic cleaner like e Z all is an important first step. A good bath will remove a lot of the smells attracting the flies. Next, most of us reach for a fly spray – here you have several options. Pyrethrins are natural compounds derived from chrysanthemum flowers, pretty effective but they break down quickly in sunlight and have little residual effect. Permethrins are the synthetic version; they last longer and are more stable. Essential oils are derived from plants; some help repel bugs others make it harder for the bugs to find the horse. Some excellent essential oils are citronella, peppermint, lavender, tea tree, thyme, cedarwood, lemon grass, eucalyptus, basil & geranium. My favorite recipe is 1 qt water in a spray bottle, 2 oz citronella oil and .5 – 1oz of any of the above-mentioned essential oils. Shake well before spraying. You can also add 1 oz of a concentrated 10% permethrin product to the mix if the flies are really bad. Spray horses in the morning, lasts all day for me.
Some other options are physical barrier protections; fly masks, bonnets, fly sheets, leg coverings made of mesh or a fine screening material can help keep flies off the horse. Be aware, a horse can destroy these on fencing, trees, bushes or with the help of pasture mates!
I hope some of this information is helpful! I will put some links to sources in the comments!