How to Get Rid of Horse Flies
A large, stout fly with huge eyes that pursues people, horses and cattle for blood. Females slice skin with blade-like mouthparts, causing a sharp, painful bite. If you are seeing them in yards and on patios and in woods and along trails, the steps below will help you clear them out and keep them from coming back.
Quick answer
- Wear light-colored long sleeves near ponds and pastures
- Use a repellent on skin and clothing
- Stay in shaded areas, since horse flies prefer sun
Horse fly bites are painful and can swell; they rarely transmit disease to people in the US.
Confirm you have horse flies
Start by confirming the bug. Horse Flies have a few features that set them apart. Adults measure 10–30 mm (up to about 1.2 in) and are usually black, brown and gray. Look for these features:
- Large, heavy body with very large, often iridescent eyes
- Clear or dark-tinted wings held apart at rest
- Persistent circling around people near water
They are most often confused with house fly and blow fly. See the full horse fly profile for side-by-side details.
Why you have horse flies
Horse Flies live outdoors and find people by sensing carbon dioxide, body heat and movement. Tall grass, brush, standing water and shady, humid areas support large populations. Pets and wildlife can carry them close to the house. They are most active in summer, so expect to see more of them then.
When you'll see horse flies
Horse Flies are most active in summer. Summer heat speeds up development, so populations can grow quickly.
Typical places to check: yard or patio, woods or trails and near water.
Step-by-step: getting rid of horse flies
Step 1: Wear light-colored long sleeves near ponds
Wear light-colored long sleeves near ponds and pastures. Keep notes on where you still see activity so you can focus your effort.
Step 2: Use a repellent on skin
Use a repellent on skin and clothing. Combine this with the other steps rather than relying on it alone.
Step 3: Stay in shaded areas
Stay in shaded areas, since horse flies prefer sun. Keep notes on where you still see activity so you can focus your effort.
Natural and low-toxicity options
These methods work well alongside the steps above and keep chemical use to a minimum:
- Use an EPA-registered repellent on exposed skin, following the label.
- Treat clothing and gear with permethrin where appropriate.
- Wear long sleeves and pants tucked into socks in high-risk areas.
- Shower soon after coming indoors.
If you do use a pesticide, choose one labeled for this pest and the place you're treating, and follow the label exactly. The label is the law.
When to call a professional
Consider a professional yard treatment if bites are frequent despite personal protection, but personal precautions remain the most reliable defense against horse flies.
How to keep horse flies from coming back
- Mow grass regularly and clear brush at the edge of the yard.
- Remove standing water every week.
- Keep play areas and patios away from wooded borders.
- Protect pets with veterinarian-recommended products.
Safety notes
Horse fly bites are painful and can swell; they rarely transmit disease to people in the US.
Call 911 right away if someone has trouble breathing, swelling of the face or throat, dizziness or a racing heartbeat after a bite or sting.
About flies & mosquitoes
The horse fly is one of the flies & mosquitoes. Flies have only one pair of working wings; the second pair is reduced to small balancing knobs called halteres. They go through complete metamorphosis, and the larvae, called maggots, need moist organic material such as garbage, soil, drain film or standing water.
Fly problems are almost always breeding-site problems. Finding and removing the moist material where larvae develop works far better than swatting adults.
Frequently asked questions
What is the fastest way to get rid of horse flies?
Wear light-colored long sleeves near ponds and pastures. Most people see a clear drop in activity within one to three weeks when they combine this with sealing entry points and removing whatever attracts them.
Are horse flies dangerous?
Horse fly bites are painful and can swell; they rarely transmit disease to people in the US.
When are horse flies most active?
Horse Flies are most active in summer.
What do horse flies look like?
Large, heavy body with very large, often iridescent eyes. Adults measure 10–30 mm (up to about 1.2 in).