What is the best spray for horse flies?
The best sprays for horse flies are those containing high concentrations of Pyrethrins or Permethrin, such as UltraShield EX or Pyranha Wipe 'N Spray, which provide both instant knockdown and long-lasting repellency. Because horse flies are visual hunters attracted to movement and carbon dioxide, oil-based sprays often work better than water-based ones because they "stick" to the coat and maintain a stronger scent barrier. For horses sensitive to chemicals, specialized fatty acid-based sprays confuse the fly's directional sensors, making the horse effectively invisible to the pest.
How to get rid of horse flies fast or permanently?
To get rid of horse flies fast, you must use physical traps like sticky barriers because horse flies are notoriously resistant to standard chemical sprays. Permanently reducing their population requires eliminating standing water and mud where they breed and using fly predators to target larvae before they mature. Since adult horse flies can fly long distances, a combination of stabled fans, protective fly sheets, and timed-release misting systems in the barn provides the most reliable long-term relief.
Can you put fly spray on a wet horse?
No. You should generally avoid putting fly spray on a wet horse because the water can dilute the active ingredients, significantly reducing the product's effectiveness and duration. On a saturated coat, the spray may simply "run off" the hair rather than bonding to the shaft, and in some cases, trapping moisture against the skin with an oil-based spray can cause skin irritation or rain rot. If you must apply it after a bath, use a sweat scraper to remove all excess water and allow the horse to air-dry until the coat is merely damp before spraying.
How long do horse fly sprays last?
Basic water-based sprays containing pyrethrins tend to offer a 4-hour protection window. Oil-based or coat-conditioning sprays last longer, usually 4–8 hours, while providing added shine to the coat. Permethrin-based sprays are among the most durable, offering protection for 1-3 days under normal conditions, with some formulas claiming up to 14 days of residual effectiveness on the coat if the horse isn't washed or heavily sweated. Concentrate formulas that are diluted and applied can also extend duration depending on the dilution ratio.
Factors that shorten effectiveness include rain, sweating, rolling in dirt, and UV exposure, while factors that extend it include dry conditions, proper application coverage, and oil-based carriers. For best results, reapply fly spray daily or every other day during peak fly season.
Interested in more horse products?
Protect your horse from flies and pests especially during spring and summer seasons with more of our fly and insect control collections available in our catalog including fly masks, fly sheets, fly sprays, and fly traps & baits.
Can I purchase Horse Fly Sprays online?
Absolutely. Don’t miss our top-rated Horse Grooming & Tack Supplies too! You might qualify for free shipping — just add the item to your cart to find out. Also, our Horse Essentials often include free delivery.