6 Horse Fly Strike Treatments That Old Farmers Swear By

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First Step: Identifying a Fly Strike Wound

Before you can treat it, you have to know what you’re looking at. A fly strike, or myiasis, isn’t just a few fly bites. It’s a full-blown infestation where flies have laid eggs in an open wound or on damp, soiled fleece or hair, and those eggs have hatched into flesh-eating maggots.

Look for a patch of matted, wet-looking hair, often with a foul, sweetish odor of decay. The skin underneath will be raw, inflamed, and weeping fluid. If you part the hair, you will see the horrifying sight of tiny, writhing larvae burrowed into the tissue. The horse will likely be agitated, trying to bite or kick at the area, or may seem lethargic and depressed from the pain and toxic shock.

Finding a fly strike is an emergency. Your first move should always be to assess the severity. If the wound is extensive, deep, or the horse shows signs of shock, your first and only step is to call a veterinarian immediately. These home remedies are for small, localized strikes caught early or for immediate first aid while you wait for professional help.

Treatment 1: Cleanse with a Saline Solution

Your first instinct might be to douse the area with the strongest stuff you have, but that can do more harm than good. Harsh antiseptics like hydrogen peroxide can damage healthy tissue and slow down the healing process. The old-school approach starts with something much gentler: a simple saline solution.

To make it, just dissolve one to two teaspoons of table salt into a pint (two cups) of boiled, cooled water. The goal is to create a solution that mimics the body’s own fluids, so it cleanses without stinging or causing cellular damage. This isn’t about killing the maggots; it’s about flushing the wound of filth, debris, and some of the surface-level larvae.

Use a syringe (without the needle) or a squeeze bottle to gently irrigate the wound. The gentle pressure helps dislodge gunk and maggots without driving them deeper into the tissue. This step prepares a clean canvas for the more direct treatments that follow and gives you a clearer view of the damage you’re dealing with.

Treatment 2: Smother Larvae with Petroleum Jelly

Maggots have to breathe. This simple biological fact is the key to one of the most effective, non-toxic methods for getting them out of your horse. A thick, generous coating of petroleum jelly or a similar heavy ointment over the entire affected area suffocates the larvae.

Don’t be shy with the application. You want to create an airtight seal over the wound and surrounding hair. The maggots will begin to migrate to the surface in search of oxygen, making them much easier to remove. After about 10 to 15 minutes, you can gently wipe away the jelly, and most of the larvae will come with it.

This method has a clear trade-off: it’s incredibly messy. You’ll have a greasy, maggot-filled glob to clean up. But the upside is huge. It’s cheap, completely non-toxic to the horse’s already-traumatized skin, and it works by forcing the invaders to evacuate on their own terms. Follow up with another saline flush to clear away any remaining residue.

Treatment 3: Apply Pine Tar as an Antiseptic

Once the wound is clean and the larvae are gone, the focus shifts to protection. This is where pine tar comes in. For generations, farmers have kept a can of this sticky, black substance in the barn for everything from sealing cracked hooves to treating wounds.

Pine tar is a natural antiseptic and a powerful fly repellent. Its thick, tacky consistency creates a physical barrier over the wound, protecting it from dirt and bacteria. More importantly, its pungent odor is detestable to flies, which will give the raw skin a chance to heal without being immediately re-infested.

Apply a thin layer over the cleaned, dry wound. Be warned: it’s incredibly sticky and will get on everything, so wear gloves. While its messiness is a drawback, its dual-action ability to both medicate and repel makes it an invaluable tool. It keeps the wound safe while actively preventing the problem from starting all over again.

Treatment 4: Dust with Diatomaceous Earth

This treatment is less for the wound itself and more for creating a hostile perimeter. Food-grade diatomaceous earth (DE) is a fine powder made from fossilized algae. On a microscopic level, it’s incredibly sharp and abrasive to insects.

After you’ve cleaned and treated the wound, let the area dry. Then, lightly dust the surrounding hair with food-grade DE. Do not put it directly into the open, weeping wound, as it’s a desiccant and can dry out the healing tissue. The goal is to create a "moat of death" for any newly hatched larvae or curious flies that land near the injury.

It’s critical to use only food-grade DE, not the kind used for pool filters, which is chemically treated and toxic if ingested. Also, be mindful of the dust. Neither you nor your horse should inhale it, so apply it gently on a calm day. This is a great preventative step to protect a healing area.

Treatment 5: Craft a Vinegar Fly Repellent

While potent treatments like pine tar protect the wound, you still need to manage the flies on the rest of the horse. A simple, homemade fly spray can make a world of difference. The base for many old-time recipes is apple cider vinegar (ACV).

A common mixture is one part ACV to two parts water, with a small squirt of mild dish soap to help it stick to the coat. Some folks add a few drops of essential oils known to repel insects, such as:

• Citronella
• Eucalyptus
• Lemongrass
• Lavender

This isn’t a chemical pesticide; it’s a deterrent. It won’t last all day, especially if the horse is sweating, so you’ll need to reapply it frequently. But for a low-cost, non-toxic way to reduce the overall fly load on your animal, it’s hard to beat. Keep a spray bottle handy in the barn for quick applications before turnout.

Treatment 6: Create a Simple Gauze Barrier

Sometimes the best medicine is simply a good barrier. Depending on the location of the fly strike, covering the wound can be the most effective way to ensure it heals cleanly. A physical barrier prevents flies from landing, keeps dirt out, and stops the horse from aggravating the injury.

Use sterile gauze pads to cover the wound, then secure them with vet wrap. The key is to wrap it snugly enough to stay on, but not so tight that you restrict blood flow. You should be able to easily slip two fingers under the wrap. This is crucial; a wrap that’s too tight can cause serious damage.

This method requires daily attention. You must remove the bandage every day to check the wound for signs of infection (pus, increased swelling, heat) and to let it air out. A moist, warm environment under a bandage can become a breeding ground for bacteria if not managed properly. This is a great option for leg or body wounds, but less practical for areas with a lot of movement, like joints.

Prevention: Key Manure Management Practices

All these treatments are reactive. The real solution is proactive. Flies are drawn to two things: moisture and manure. If you can control those, you can drastically reduce your fly population and the risk of fly strike.

Your manure pile is ground zero for fly breeding. It should be located as far away from your barn and pastures as is practical. Turning the pile regularly or properly composting it generates enough heat in the center to kill fly eggs and larvae, disrupting their life cycle. Don’t let manure build up in or around run-in sheds.

Inside the barn, keep stalls as clean and dry as possible. Soiled, wet bedding is a prime target for egg-laying flies. Muck out daily and ensure there’s good ventilation to help things dry out. A fly problem isn’t a sign of failure; it’s a part of keeping livestock. But diligent manure and moisture management is your single most powerful tool for keeping it under control.

These time-tested remedies are about empowerment, giving you the tools to act decisively when you find a problem. They bridge the gap between discovery and professional care, blending old wisdom with practical observation. Always remember your best judgment and never hesitate to call a vet when a situation feels beyond your control.