Different Types of Insect Control Supplements for Horses

Updated September 22, 2023
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Insect defense vs. growth regulator supplements - each has its own strategy for protecting your horse from bug bites this fly season. Don’t worry, we’ll help you figure out which one is the right pick for your horse and farm.

Types of Insect Control Supplements

  • Insect defense supplements – These products help deter pesky flies and insects.
  • Insect growth regulator supplements – These formulas provide targeted ingredients to inhibit the development of house and stable flies.

Both are daily, feed-through formulas. Insect defense supplements provide an additional element of protection for your horse as they help discourage flies from bothering and biting him – helping to make riding and turnout time fun for both of you. While insect growth regulator supplements (larvicides) work by preventing house and stable fly larvae from developing into adults, which means they’ll never become those bothersome pests that fly and buzz.

Key Ingredients

itchy palomino horse in a grass paddock

Ingredients to Look for in Insect Defense Supplement

Garlic, apple cider vinegar, and brewer's yeast: These aromatic ("smelly") ingredients make your horse unappealing to biting insects. (But, contrary to popular belief, they won't make your horse smell like an Italian restaurant-most riders don't even notice a difference!)

Diatomaceous Earth: This whitish powder is made up of the fossilized remains of diatoms, a type of prehistoric, hard-shelled algae. While totally harmless to your horse, once passed in the manure, the microscopic particles have sharp edges that are said to penetrate the outer covering of worms and insects, causing dehydration and death, so they can help stop larvae from developing into adult flies.

Ingredients to Look for in Insect Growth Regulators

Diflurobenzuron and cyromazine: These insecticides act as insect growth regulators. They safely pass through your horse's GI tract with no effects on your horse, and they go to work in the manure. Both ingredients are proven to inhibit the development of larvae into adult flies, reducing the population of flies around your barn.

What to Expect When Using Insect Control Supplements

Insect defense supplements take time to reach their full benefit, generally about 4-6 weeks. It’s possible that your horse may act comfortable and happy during turnout and your rides right away, but if not, that’s ok, it may take a bit more time! Keep an eye on your horse over the first several weeks for how he looks and feels.

For growth regulators, it’s best to start feeding these to your horse a few weeks before flies typically appear in your area. Since it takes 4-6 weeks for the existing adult fly population to die off, you should start to notice fewer flies buzzing around after you’ve been giving the supplement for a few weeks. Because flies breed and develop in manure, it’s important to have all the horses on the property receiving an insect growth regulator supplement for it to manage the fly populations most effectively on your property.

Shop All Insect Control Supplements

Develop a Comprehensive Approach this Fly Season

Keeping a targeted fly deterrent formula and/or insect growth regulator supplement in your horse’s SmartPaks will help ensure that he has what he needs to help beat the bugs. There’s not one single strategy for completely managing insects, but rather a comprehensive approach that will give you the best results.

SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.