7 Fly Control Myths

Horse owners try lots of things to keep bugs away in the summer. Here’s the truth behind some of these unusual tricks.


Keeping insects away from your horse and out of your barn can seem an exercise in futility at times. While there are loads of fly-control products on the market, everyone seems to have a theory about what else can be done to keep bugs at bay.
Here’s the down-and-dirty truth about what doesn’t (and does!) keep bugs from bothering your equine friends.

Theory: Placing a penny in water in a resealable baggie and hanging it from a doorway will keep flies from entering your barn.

Conclusion: False. While the thought process behind this theory is intriguing, the method sadly doesn’t work. It’s purported that the copper penny in the water creates a prismatic effect on a fly’s eyesight, and the dizzying spectacle keeps them from approaching your horse’s dwelling.

Flies on a horse
You’d do anything to give your horse some relief from flies, but don’t waste your time with the unusual techniques that simply don’t work.

Theory: Long, cold winters will kill off over-wintering fly populations.

Conclusion: False. Entomologists report that over-wintering fly populations can survive deep in the soil; heavy snow cover can actually protect these flying insects from extreme cold. Additionally, a cold winter followed by a warm and sunny March could actually accelerate some fly cycles—what an unfair scenario!

Flies on a horse


Theory: Electric bug zappers stop flies in their tracks.

Conclusion: False. While the noise bug zappers make when they fry bugs can seem satisfying, they really do more harm than good by killing thousands of beneficial insects that don’t bother people or horses, leaving the majority of flies alive to pester us.

Flies on a horse


Theory: Ultrasonic devices will keep flies and other rodents away from your barn.

Conclusion: False. Ultrasonic pest repellers emit high-frequency sounds (above the range of human hearing) designed to repel or kill insects and rodents. Sadly, laboratory tests have shown that the majority of these devices do not work.

Flies on a horse


Theory: Vanilla-scented air fresheners repel flies and leave your barn smelling sweet.

Conclusion: False. Vanilla-scented car air fresheners may not very helpful as fly repellent in the barn, but pure vanilla has been reported to repel mosquitoes (but the sweet smell may attract bees!).

Flies on a horse


Theory: Bacon grease will help repel flies.

Conclusion: True. Because of its viscosity, bacon grease applied to the horse where flies tend to bite will result in rapid relief. Additionally, should the horse have open sores where flies have bitten him, the grease will not irritate the open wound. Petroleum jelly, also sticky, can work as well.

Flies on a horse


Theory: Dryer sheets can help repel flies when riding.

Conclusion: Possible. Though more likely to repel mosquitoes and gnats, dryer sheets contain two chemicals, linalool and beta-citronellol, that may repel flying insects. It couldn’t hurt to tuck one into your pocket or under your saddle to see for yourself!


  1. Thanks for the truth. I won’t waste my money on fly control gimmicks. I might try the dryer sheet thing, but probably not the bacon grease – that would repel me as much as the flies!

  2. Say what you will about ultrasonic devices but I have them and they work wonders both in the house and barn. Wish I could carry one with me in the pastures all the time!

  3. Adding Vitamin B1 to your waterers will result in an overload in your horse’s system which will be exuded through the skin and repel MOST insects..works for the riders too! It’s water soluable so you excrete any that you don’t need, without damaging your organs.

  4. When I was in Belize and Honduras they had several pennies in a bag with water and hung them all over to keep flies away. When I came home I did this out on my porch and have almost no flies now.

  5. When I was in Belize and Honduras they had several pennies in a bag with water and hung them all over to keep flies away. When I came home I did this out on my porch and have almost no flies now.

  6. The baggies with or without the coin work for us. Kept a lot of flies out of the barn. Not as well s fly predators but it still did work.

  7. I use pennies in bags through out the house and its pretty much fly free. I started using this method 3 years ago. Don’t forget to put a bag in the doorway.


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