Repel Insects That Bite and Annoy Horses

By: Dr. Lydia Gray | Updated March 23, 2025 by SmartPak Equine

Insects not only annoy horses, but they also spread diseases. Horse flies, mosquitoes, mites, midges, botflies, lice, and other creepy crawlers can also cause allergic reactions such as "sweet itch."

While there is no way to completely eliminate these pests, a coordinated approach can significantly reduce their numbers.

Tips for Repelling Insects

• The most commonly used method of controlling insects is to use repellent designed to be sprayed or wiped directly on horses. Spot-ons are more concentrated repellent that is applied less frequently and may be more appropriate for pasture-kept horses.
• Fly masks, boots and sheets place a physical barrier between insects and the horse.
• Horses should be kept inside during times of the day when insects are at their worst.
• Screens and fans can be used to provide inside horses with even more protection.
• Other methods to reduce insect numbers in the barn include fly traps, strips, sticks, bait, automatic misters, residual sprays and area foggers.
• Feed-through larvicides may be an additional option to consider when designing your comprehensive insect management program.
• Many horse owners also swear by insect control supplements that contain ingredients such as garlic, apple cider vinegar, and diatomaceous earth.

Environmental Management Strategies for Insect Control

Managing the environment is every bit as important as managing the horse and his immediate area. All standing water on the farm must be eliminated because this is the breeding ground for some insects. Since other insects prefer wet organic matter such as soiled bedding, not only must stalls and paddocks be cleaned frequently, the material must be removed, covered or composted.

Video on Fly Control Options

Additional Horse Owner Resources

• Use our comprehensive no-fly zone guide to fight the flies barn-wide.
• Watch this video on fly control options for all horses.
• How to keep flies off of horse's eyes.