Can you get rid of horse flies permanently? While complete, permanent eradication across a large area is very hard due to their life cycle and migratory nature, you can significantly reduce their numbers and stop horse flies biting through consistent, multi-faceted control methods.
Horse flies, also known as deer flies or greenheads, are more than just a nuisance. Their painful bites can distress livestock, pets, and people. These pests cause itching, swelling, and can even spread disease. To truly tackle the problem, you must attack them at every stage of their life cycle: egg, larva, pupa, and adult. This long-term approach is the key to successful horse fly control.
The Horse Fly Life Cycle: Where to Attack
To effectively eliminate biting flies, we first need to know how they live. Horse flies have four main stages in their life. Knowing this helps us target the weakest points.
Egg Stage
Female horse flies lay hundreds of eggs near water or wet soil. These eggs hatch quickly, usually within a week.
Larval Stage
The young larvae live in mud or shallow water. They feed on small creatures found there. This stage lasts several weeks to months, depending on the species and climate.
Pupal Stage
The larva turns into a pupa in the soil. It looks like a hard case. This stage can last a few weeks before the adult fly emerges.
Adult Stage
The adult fly emerges ready to feed. Only the female bites, as she needs blood to produce eggs. Adult flies typically live for a few weeks during the warm season. They are strong fliers and are highly attracted to movement and dark colors.
Essential Steps for Horse Fly Prevention
Stopping horse flies before they become a major problem is always easier than dealing with an infestation. Horse fly prevention requires environmental management.
Managing Wet Areas
Since their larvae need moisture, reducing standing water is crucial.
- Drain puddles immediately after rain.
- Keep gutters clean so water flows freely.
- Fix leaky hoses or outdoor faucets promptly.
- Manage irrigation to avoid overwatering fields or pastures.
Controlling Farm Debris
Adult flies need places to rest and hide during the hottest part of the day.
- Keep tall grasses cut short in areas where animals gather.
- Remove piles of rotting vegetation or organic debris near animal shelters.
Managing Livestock
Healthy animals are often better equipped to handle pests, but reducing attraction is key.
- Keep horses clean. Manure attracts many types of flies.
- If possible, rotate pastures to break the life cycle in one spot.
Top Methods to Trap and Kill Adult Horse Flies
Once the adult flies are buzzing around, trapping them becomes a primary focus. Horse fly traps are highly effective tools when placed correctly.
Types of Effective Horse Fly Traps
Different traps work in different ways. Some use visual attraction, while others use breath or CO2 to mimic a host.
Sticky Traps
These traps are simple. They use a sticky surface that captures flies on contact. They are best used in smaller, contained areas.
Color and Shape Traps (e.g., The Horse Fly “Snare”)
These traps use dark, round shapes that mimic the silhouette of a large animal. Flies are attracted to the dark, moving object.
- How they work: A large, dark ball hangs suspended. Heat from the sun warms the ball. A light-colored plastic skirt surrounds the ball. When the fly lands on the ball, it slips down into a collection bucket filled with soapy water or a killing agent.
- Placement: Place these traps where flies are most active, usually near where animals rest or graze.
CO2 and Bait Traps
These are often the most effective but also the most costly. They use carbon dioxide (CO2) gas, which mimics an animal’s breath, or attractants that smell like sweat or breath.
- These traps lure the flies in close. The flies are then sucked into a holding chamber or electrocuted.
| Trap Type | Effectiveness Level | Cost Range | Maintenance | Best Use Case |
|---|---|---|---|---|
| Sticky Traps | Low to Medium | Very Low | Daily Check | Small Patios, Paddock Gates |
| Color/Shape Traps | Medium to High | Medium | Weekly Cleaning | Pastures, Barn Areas |
| CO2/Bait Traps | Very High | High | Fuel/Attractant Refill | Large Properties, Severe Infestations |
Chemical and Non-Chemical Repellents
When you cannot trap them all, keeping them off the host is the next best thing. You need a good horse fly repellent.
Commercial Repellents
Many commercial sprays are available. They usually contain active ingredients that disrupt the fly’s ability to land or sense the host.
- Pyrethrins and Pyrethroids: These are common insecticides that offer quick knockdown. They require frequent reapplication, especially after rain or heavy sweating.
- Repellent Oils: Look for products containing ingredients like Permethrin, which has long-lasting effects on surfaces.
Natural Horse Fly Control Sprays
For those preferring fewer synthetic chemicals, natural horse fly control offers viable options. These often need more frequent application.
- Vinegar Solutions: Diluted apple cider vinegar mixed with water can act as a mild repellent.
- Essential Oils: Oils like citronella, peppermint, geranium, and cedarwood can deter flies when mixed with a carrier oil (like coconut oil) and sprayed lightly. Always patch-test on a small area first.
Physical Barriers for Protection
The best way to stop horse flies biting is to block access entirely.
- Fly Sheets and Masks: Lightweight mesh sheets cover the horse’s body. Specialized fly masks protect the eyes and face, areas where deer flies often target.
- Fans: Flies are poor flyers in windy conditions. Placing large, oscillating fans near feeding or resting areas can keep the air moving enough to deter them.
Targeting Larvae: Treating Breeding Grounds
If you want to get rid of horse flies permanently, you must address the larval stage in wet soil. This is the hardest part, as these areas are often muddy or inaccessible.
Water Treatments
For small, manageable areas of standing water or boggy ground that cannot be drained:
- Insect Growth Regulators (IGRs): Products containing ingredients like Methoprene can be applied to the water or mud. IGRs stop the larvae from maturing into biting adults. They are generally safer for non-target organisms than broad-spectrum insecticides.
- Bacillus thuringiensis israelensis (Bti): This naturally occurring bacterium targets mosquito and black fly larvae but can also affect some stages of horse fly larvae. It is often sold as “dunks” or granules for water treatment.
Soil and Mud Treatments
If the larvae are deep in the mud near a pond edge, treatment is challenging.
- Timing is Key: Treat the mud right before the emergence period (usually late spring/early summer).
- Drying Out: If possible, try to temporarily dry out small breeding areas using lime or absorbent materials, which makes the environment unsuitable for larvae.
Getting Rid of Deer Flies Specifically
Deer flies are closely related to horse flies and often appear earlier in the season. The methods for getting rid of deer flies are very similar, but deer flies tend to hunt closer to wooded edges.
- Focus on trapping and repellent use near the edge of woods or brushy areas where they rest.
- Deer flies are often more attracted to movement than horse flies, making visual traps very effective.
Treating Horse Fly Bites on Animals and People
Despite your best efforts, bites will happen. Knowing how to handle them is important for comfort and preventing infection.
For Animals
Horse fly bites are often deep wounds because the fly uses sharp, scissor-like mouthparts to create a pool of blood to feed on.
- Clean the Area: Immediately wash the bite site gently with mild soap and water or an antiseptic solution.
- Soothe Swelling: Apply a cold compress or ice wrapped in a cloth to reduce swelling.
- Topical Treatments: Use veterinarian-approved salves or creams designed to reduce itching and inflammation. If the animal excessively scratches the area, use fly sheets to prevent secondary infection.
For People
When you get a bite, the pain is immediate, and the itch follows.
- Stop the Itching: Apply an ice pack immediately after the bite.
- Use After-Bite Products: Products containing hydrocortisone or calamine lotion help reduce the inflammatory reaction.
- Watch for Infection: If the wound becomes hot, red, or oozes pus, seek medical advice. Treating horse fly bites effectively means preventing secondary bacterial infection.
Advanced Strategies: The Best Horse Fly Treatment Plan
A truly successful approach combines multiple methods. There is no single best horse fly treatment; rather, it is a strategy that layers defense and offense.
Integrated Pest Management (IPM) Approach
This means using different tools at different times.
- Early Spring (Pre-Emergence): Focus on habitat modification—drain water sources and remove heavy debris.
- Late Spring/Early Summer (Peak Hatch): Deploy high-powered traps (CO2 or visual snares) in primary fly zones. Begin daily use of homemade horse fly spray or commercial repellents on animals.
- Mid-Summer (Sustained Attack): Maintain traps and reapply repellents as needed. Check animals daily for new bites.
- Late Summer/Fall (Decline): Reduce active trapping efforts, focusing instead on cleaning up the environment for the next season.
Creating Fly-Free Zones
Focus your resources where they matter most: near where people or animals spend the most time resting or eating.
- Place fans and sticky traps near stalls, shelters, and shaded resting spots.
- This concentrates your efforts on reducing the local population that directly interacts with the hosts.
Making Your Own Homemade Horse Fly Spray
If commercial options are too costly or you need frequent, light applications, a homemade horse fly spray can help refresh protection.
| Ingredient | Purpose | Amount (Example Ratio) | Notes |
|---|---|---|---|
| Water (Distilled) | Base | 1 Cup | Helps dilute strong oils. |
| Apple Cider Vinegar (ACV) | Repellent/pH Balancer | 1/2 Cup | Flies dislike the scent. |
| Witch Hazel or Rubbing Alcohol | Emulsifier/Drying Agent | 1/4 Cup | Helps mix oil and water. |
| Essential Oils (Citronella, Geranium, Peppermint) | Active Deterrent | 20-30 Drops Total | Use sparingly; always shake well before use. |
Application Tip: Always use a high-quality spray bottle. Since oils and water separate, you must shake this mixture vigorously before every single spray to ensure the repellent oils actually reach the target.
Maintaining Long-Term Success
Getting rid of horse flies permanently requires persistence. If you stop control measures, the population will quickly rebound, especially in warm, moist climates.
Regular Monitoring
Keep track of when fly activity peaks in your area. This information helps you know when to start your prevention methods earlier the following year. Use simple tally sheets near barn doors to count flies caught or seen daily.
Adapting Your Strategy
If one type of trap stops working, switch tactics. If the larvae are surviving in one pond, explore new IGR treatments. Flexibility is crucial in fighting resilient pests. Consistent application of repellent and diligent trap maintenance are non-negotiable parts of any lasting horse fly control plan.
Frequently Asked Questions (FAQ) About Horse Flies
Q1: Why are horse flies so much more aggressive than stable flies?
Horse flies are generally more aggressive because of how they feed. Stable flies bite primarily to take a blood meal, often landing gently first. Horse flies are attracted to movement and often attack quickly without landing first. They use sharp, blade-like mouthparts to slash the skin open to create a pool of blood, making their bites much more painful and dramatic than stable flies.
Q2: How long does it take for horse fly traps to start working?
The effectiveness depends on the trap type and placement. CO2 traps can show results within hours if flies are abundant. Simple sticky traps might take a few days to start catching a significant volume. For best results, traps should be placed where flies are actively searching for hosts, not just randomly placed in the pasture.
Q3: Are there natural ways to protect my dog from deer flies?
Yes. For dogs, use specialized topical spot-on treatments recommended by your vet. You can also use diluted essential oil sprays (like diluted cedarwood) applied lightly to the dog’s collar or back blanket, avoiding the eyes and mouth. Fans are also excellent at keeping flies away from dogs resting outside.
Q4: Can I use manure management to reduce the horse fly population?
Yes, managing manure is a vital part of reducing overall fly populations. While horse flies prefer moist soil and water for their larvae, many other biting flies (like stable flies) breed directly in manure piles. Regularly cleaning and composting manure away from living areas reduces the overall “fly pressure” in your environment.
Q5: How deep do horse fly larvae live in the soil?
Horse fly larvae typically live in the top few inches of wet soil or mud along the edges of ponds and slow streams. They usually stay shallow enough that treatments like Bti or surface-applied IGRs can reach them effectively, provided the soil remains moist. Drying out the area is often the most effective natural kill method for larvae.