How to Deter Annoying Horse Flies

← Pest & Insect Control | Insect Repellents & Prevention

Quick answer

• Know your enemy: Horse flies are attracted to dark colors and CO2.
• Wear light-colored, loose-fitting clothing.
• Use EPA-approved repellents containing DEET, Picaridin, or Oil of Lemon Eucalyptus.
• Consider physical barriers like head nets or treated clothing.
• Keep your campsite clean and manage garbage to avoid attracting them.
• Move if a swarm is overwhelming; they often have specific feeding zones.
• Bring a fan for your tent or seating area.

What to check first (do this before you drive out)

Before you load up the truck and head for the hills, take a minute to get smart about the horse fly situation. It’s way better to be prepared than to be miserable.

• Land manager / legality: Who owns this patch of dirt? Is it National Forest, BLM, State Park, or private? Different outfits have different rules. Check their websites or call ahead. You don’t want to get shut down for something you could have easily known.
• Access/road conditions: Horse flies love damp areas, and so do the roads leading to them. Is that dirt track a two-wheel-drive nightmare after a rain? Do you need high clearance or 4WD? A quick check on recent conditions can save you a tow.
• Fire restrictions + weather + wind: Horse flies are worse when it’s hot and humid. Check the forecast. Also, fire restrictions are serious business. Know the current rules, and be aware of wind – it can help keep flies off, but also spread fire.
• Water plan + waste plan (Leave No Trace): Horse flies breed near water. If you’re camping near a stream or pond, expect more of them. Plan how you’ll get your water and, more importantly, how you’ll pack out everything you pack in. No exceptions.
• Safety (wildlife, distance to help, comms): While horse flies are just annoying, know what else is out there. Are there bears? What’s the nearest ranger station or hospital? Cell service is usually a joke in the backcountry. Let someone know your itinerary.

Step-by-step (field workflow)

Okay, you’ve arrived. The sun is beating down, and you can already feel the buzz. Here’s how to handle it.

1. Set up camp strategically.

• What to do: Choose a spot that might get a decent breeze. Avoid areas right next to stagnant water if possible.
• What “good” looks like: A spot that feels a bit cooler and less buggy from the get-go.
• Common mistake: Plopping down the tent wherever there’s flat ground, often right in a fly hotspot. Avoid this by scouting a bit.

2. Wear the right gear.

• What to do: Put on light-colored, loose-fitting clothing. Think long sleeves and pants.
• What “good” looks like: Feeling protected and less like a buffet.
• Common mistake: Wearing dark, tight clothing. Flies love to land on dark surfaces and can bite through thin, stretched fabric.

3. Apply repellent.

• What to do: Use an EPA-registered repellent on exposed skin and clothing. Products with DEET, Picaridin, or Oil of Lemon Eucalyptus are good bets.
• What “good” looks like: A protective shield that makes you less appealing to biting insects.
• Common mistake: Skimping on application or missing spots. Flies can find those tiny uncovered areas in a heartbeat. Reapply as directed.

4. Deploy physical barriers.

• What to do: If they’re really bad, consider a head net. You can also find clothing treated with permethrin.
• What “good” looks like: Uninterrupted peace without swatting.
• Common mistake: Thinking a flimsy bandana is enough. Horse flies are persistent; you need real protection.

5. Manage your trash.

• What to do: Keep all food scraps and garbage sealed in bear-resistant containers or bags.
• What “good” looks like: A clean camp that doesn’t smell like a free meal.
• Common mistake: Leaving food wrappers out or not securing the trash. This is like ringing the dinner bell.

6. Create airflow.

• What to do: If you have a battery-powered fan, set it up at your picnic table or in your tent.
• What “good” looks like: A constant, gentle breeze that makes it hard for flies to land.
• Common mistake: Thinking a little whirring fan won’t make a difference. It really does help.

7. Minimize attraction.

• What to do: Avoid dark colors and strong, sweet perfumes or colognes.
• What “good” looks like: Being as uninteresting as possible to a hungry fly.
• Common mistake: Wearing your favorite black t-shirt and spraying yourself with cologne. You’re basically asking for it.

8. Know when to move.

• What to do: If a particular spot is just swarming and unbearable, pack up and try a different location a few hundred yards away.
• What “good” looks like: Finding a less infested area where you can actually enjoy your trip.
• Common mistake: Sucking it up and enduring misery. Sometimes, a tactical retreat is the smartest move.

Common mistakes (and what happens if you ignore them)

Mistake	What it causes	Fix
Wearing dark, tight clothing	Increased fly landings and bites, discomfort	Switch to light-colored, loose-fitting natural fibers or synthetics.
Neglecting repellent application	Exposed skin gets bitten, leading to painful welts and itching	Apply EPA-approved repellents thoroughly to all exposed skin and clothing. Reapply as needed.
Camping near stagnant water	Constant swarm of flies, breeding grounds are nearby	Scout for a location with better airflow and further from obvious water sources.
Leaving food or garbage exposed	Attracts flies and other pests, making your camp a target	Secure all food and trash in sealed containers or bags.
Using sweet-smelling products	Attracts flies and other biting insects	Opt for unscented soaps, lotions, and avoid perfumes/colognes.
Not having a plan for extreme heat	Flies thrive in heat, making them more aggressive and miserable for you	Check the weather and have cooling strategies (fans, shade, hydration).
Ignoring wind conditions	Flies can be relentless in calm air, but strong winds can help	Utilize breezy spots and consider a small fan if air is still.
Not packing out all waste	Pollutes the environment and can attract more pests	Follow Leave No Trace principles strictly; pack out everything you pack in.
Assuming all bugs are the same	Underestimating the horse fly’s tenacity and biting power	Understand their habits and use targeted deterrents.
Not checking land manager regulations	Unknowingly breaking rules, potential fines or eviction	Always verify rules and restrictions with the managing agency before your trip.

Decision rules (simple if/then)

• If the forecast calls for high heat and humidity, then pack extra repellent and consider a portable fan because these conditions are prime horse fly season.
• If you’re setting up camp near a marsh or slow-moving water, then expect more horse flies, so prioritize physical barriers like head nets.
• If you notice flies are relentlessly targeting dark colors, then switch to lighter clothing immediately because you’re acting as a beacon.
• If you forgot bug spray, then try to find a location with strong, consistent wind because moving air is a natural deterrent.
• If you’re planning a hike, then apply repellent to your clothing as well as your skin because flies can bite through thin fabric.
• If your campsite is attracting a swarm, then check your garbage and food storage first because an unsecured meal is a major draw.
• If you have a history of severe reactions to insect bites, then carry an antihistamine and be extra cautious with repellent and protective gear because horse fly bites can be particularly nasty.
• If you’re by yourself and being swarmed, then consider moving to a different spot because they can be territorial and concentrated.
• If you see horse flies hovering around your face, then use a gentle puff of air or a slow wave of your hand to dislodge them without swatting aggressively, which often just agitates them further.
• If you’re camping in an area known for horse flies, then research specific local recommendations from park rangers or online forums because some areas have unique fly behaviors.
• If you’re sensitive to chemical repellents, then prioritize permethrin-treated clothing and head nets because they offer a physical barrier without skin application.

FAQ

Are horse flies attracted to sweat?

Horse flies are attracted to carbon dioxide, heat, and certain scents, which can be amplified by sweat. This makes you more appealing when you’re active.

Can I use natural repellents for horse flies?

Some natural oils like citronella or eucalyptus might offer minor, temporary relief, but they are generally not as effective or long-lasting as EPA-registered repellents for serious horse fly problems.

What’s the best time of day for horse flies?

Horse flies are typically most active during daylight hours, especially on warm, sunny days. They tend to be less bothersome at dawn, dusk, and during cooler or overcast weather.

Do horse flies bite through clothing?

They can bite through thin, tight-fitting clothing. Loose-fitting, thicker natural fibers or treated synthetics offer better protection.

How do I know if I’m allergic to horse fly bites?

Symptoms of a severe reaction can include large swelling, redness extending beyond the bite area, fever, or hives. If you suspect an allergic reaction, seek medical attention.

Are horse flies dangerous to pets?

Yes, horse flies can bite and bother pets, especially livestock. They can transmit diseases in some cases, though this is less common in many recreational areas. Protect your pets with appropriate repellents if needed.

Why do they bite so hard?

Horse flies have strong, piercing mouthparts designed to cut skin and lap up blood, which is why their bites are often painful and leave significant welts.

What can I do if I get a bite?

Clean the bite area with soap and water. Apply a cold compress to reduce swelling and itching. Over-the-counter antihistamines or hydrocortisone cream can help manage symptoms.

Are horse flies worse in certain regions of the US?

Horse flies are common throughout the US, but they tend to be more prevalent in areas with ample moisture and vegetation, such as the Southeast, Midwest, and along river valleys and coastlines.

Can I use a fan to keep flies away from my tent?

A small, battery-powered fan can create airflow that makes it difficult for flies to land, offering some relief both inside and outside your tent.

What this page does NOT cover (and where to go next)

• Specific campsite reservation systems or fees. Check the official page for the specific site/agency.
• Detailed identification of all biting insects. This page focuses on horse flies.
• Medical treatment protocols for severe allergic reactions. Consult a healthcare professional.
• Advanced wilderness survival techniques. Focus on preparedness for common issues.
• Regulations on firearms or hunting in specific areas. Always check local laws and land manager rules.