How to Get Rid of Horse Flies: The Complete Guide

Understanding Horse Flies

Before you can get rid of horse flies, you need to understand what makes them different from every other flying pest. Horse flies (family Tabanidae) include several species: horse flies (Tabanus), deer flies (Chrysops), greenheads (Tabanus nigrovittatus), and yellow flies (Diachlorus ferrugatus). They share common traits that make them uniquely challenging to control.

Why Horse Flies Bite

Only female horse flies bite. They need a blood meal to develop and lay their eggs — it's biological, not aggressive. Males feed on pollen and nectar. The females have specialized scissor-like mouthparts (mandibles) that slash the skin and lap up the pooling blood, which is why horse fly bites are so painful and often bleed after the fly leaves.

How Horse Flies Find You

Horse flies are visual predators. This is the most important fact for controlling them. Unlike mosquitoes (which use CO₂ and body odor) or house flies (which follow food scent), horse flies locate hosts primarily by sight. They're attracted to:

• Dark colors — especially black, dark blue, and dark brown
• Movement — slow, steady motion triggers their attack response
• Size — they're drawn to large objects that look like potential hosts
• Polarized light — reflected from water surfaces and dark materials

This visual hunting behavior is why most conventional pest control methods fail against horse flies — they're designed for scent-following or light-attracted insects.

Where Horse Flies Come From

Female horse flies lay eggs on vegetation overhanging wet soil or water. The larvae develop in moist soil near:

• Pond and lake margins
• Stream and creek banks
• Marshes and wetlands
• Drainage ditches
• Consistently damp areas in fields and yards

Adults emerge in late spring and are most active from June through September, with peak activity during the hottest, sunniest hours of the day (10 AM – 4 PM).

Methods That DON'T Work for Horse Flies

Let's clear up the misconceptions first. These popular methods are designed for other insects and are largely ineffective against horse flies:

Bug Zappers — Ineffective

Bug zappers use UV light to attract insects. Horse flies are not attracted to UV light. A University of Delaware study documented that of ~10,000 insects killed by a residential bug zapper over one summer, less than 0.2% were biting flies. Bug zappers primarily kill moths, beetles, and beneficial insects while leaving horse flies untouched.

Citronella and Essential Oils — Ineffective

Citronella candles, lemongrass oil, and other scent-based products target mosquitoes and other scent-following insects. Horse flies navigate by vision, not smell. These products have virtually no deterrent effect on Tabanid flies.

Ultrasonic Devices — Ineffective

Electronic devices claiming to repel insects with sound waves have been repeatedly tested and shown to have no effect on any fly species. The FTC has issued warnings about misleading claims from some manufacturers.

Fly Paper and Sticky Strips — Minimally Effective

Standard yellow sticky traps attract flies that respond to the color yellow — primarily house flies and fruit flies. Horse flies are attracted to dark colors, not yellow. Dark-colored sticky panels can catch some horse flies but fill quickly, are messy, and don't significantly impact populations.

Methods That PARTIALLY Work

Chemical Repellents (DEET, Permethrin)

Personal repellents containing DEET (skin) or permethrin (clothing) can deter horse flies for 30–90 minutes. They provide temporary personal protection but:

• Require constant reapplication (especially with sweat and water)
• Don't kill or trap flies
• Have zero effect on the local fly population
• Pose environmental concerns (permethrin is toxic to aquatic life and bees)
• Some Tabanus species show increasing resistance

Verdict: Useful as supplemental personal protection, but not a solution for your property.

Fly Masks and Fly Sheets (for Horses)

Physical barriers protect individual animals' faces and bodies. They're effective personal protection for horses but don't reduce fly populations or protect people.

Fans and Air Curtains

Strong airflow can deter horse flies in enclosed or semi-enclosed spaces (barns, covered patios). Horse flies are powerful flyers, so fans must produce significant wind speed to be effective. This only works in sheltered areas — not in open yards or pastures.

Habitat Modification

Reducing standing water and wet areas on your property can limit local breeding sites. However, horse flies can fly over a mile from their breeding site, so this only helps if the wet areas are on your own property and you can effectively drain them — which often isn't feasible.

The Method That WORKS: Visual Traps

The most effective, scientifically validated method for controlling horse flies is the visual ball trap. Here's why:

It targets the fly's actual behavior. A dark, 3D lure mimics the visual profile of a large animal. Horse flies approach the lure the same way they'd approach a horse or person. When they land and are disturbed by the trap structure, their instinct is to fly upward — directly into a capture cage above the lure.

This approach is supported by:

• USDA Agricultural Research Service / Cornell University (2018) — Visual traps outperformed all other non-chemical methods for Tabanus and Chrysops species
• University of Florida IFAS Extension — Recommends dark-lure visual traps as the primary non-chemical control for horse flies
• European field research — Studies in France, UK, and Scandinavia documented 85–95% reduction in horse fly landings on livestock near visual traps

The Fly Cage: A Better Visual Trap

The Fly Cage was designed by Tom Pray, a licensed entomologist with a B.S. in Entomology from the University of New Hampshire and 27 years of professional pest control experience. His company, Ecotech Pest Control Services, serves over 1,000 clients.

The Fly Cage improves on the visual trap concept with:

• Powder-coated aluminum frame — Multi-season durability, no rust or UV degradation
• Marine-grade mesh — Weatherproof capture cage built for years of outdoor use
• Patented design — Engineered specifically for Tabanid flies
• 2-minute setup — Hang from any branch, hook, or pole. No tools.
• ~5 lb weight — Easy to reposition for optimal placement
• ½-acre coverage per trap
• Zero ongoing cost — No chemicals, no electricity, no bait, no replacement parts
• Made in Fishers, Indiana

A Complete Horse Fly Control Strategy

For the best results, combine multiple approaches:

1. Deploy visual traps (primary) — The Fly Cage should be your first line of defense. Place in full sun, open areas, between fly breeding habitat and your living/working space.
2. Reduce breeding habitat (where possible) — Drain standing water, clear vegetation from pond edges, fix drainage issues on your property.
3. Use personal repellent (supplemental) — DEET for skin, permethrin for clothing, when venturing into high-activity areas beyond trap coverage.
4. Wear light-colored clothing — Horse flies are attracted to dark colors. Light colors (white, khaki, pale yellow) are less attractive.
5. Time outdoor activities — Horse flies are least active in early morning and late evening. Peak activity is 10 AM – 4 PM on sunny days.
6. Physical barriers — Fly masks/sheets for horses, fans for covered areas.

The trap does the heavy lifting by removing breeding females from the population. The other measures provide supplemental protection during peak activity.

Expected Timeline

• Week 1: Trap begins catching flies; you notice reduced activity near the trap
• Weeks 2–4: Significant population reduction as breeding females are removed
• Month 2–3: Cumulative effect — fewer larvae developing means fewer adult flies emerging
• Year 2+: Consistent trap use leads to measurably lower baseline fly populations each season