How To Make Horse Fly Trap: Effective & Cheap

Can I make a horse fly trap at home? Yes, you absolutely can build an effective and cheap DIY horse fly trap using simple household items.

Horse flies, often called “deer flies” or “greenheads,” are more than just annoying pests. They bite hard, causing pain, stress, and sometimes spreading diseases to horses and other livestock. While sprays and physical barriers offer some protection, trapping them offers a long-term, chemical-free solution for natural horse fly control. This guide will show you how to build a few proven designs that work well for attracting and trapping horse flies around your stable, pasture, or backyard.

Why Trapping Works: Grasping Fly Behavior

To build the best horse fly trap design, we must first know how these biting insects think. Horse flies are drawn to heat, movement, and carbon dioxide ($\text{CO}_2$)—the very things a large animal like a horse produces. They are visual hunters. They look for dark, moving objects that mimic their prey.

Horse Fly Attraction Factors:

Heat: They seek out warm bodies.
Carbon Dioxide ($\text{CO}_2$): Breath is a major attractant.
Movement: Shadows or silhouettes that move catch their eye.
Color: Dark colors, especially black or dark blue, are highly attractive.

Effective trap for biting flies on horses utilize these natural lures to draw the flies away from the animals and into a collection area from which they cannot escape.

Method 1: The Hanging Ball Trap (The Best for Visual Attraction)

The hanging ball trap, often called the “sweet-smelling ball trap,” is one of the most famous and simplest easy to build fly trap for livestock. It relies on mimicking a moving, warm host.

Materials for Horse Fly Trap

Gathering the right materials for horse fly trap is the first step. You want things that are durable and readily available.

Component	Suggested Material	Purpose
Lure/Ball	Large black exercise ball, dark plastic buoy, or even a dark-painted beach ball.	Mimics the visual silhouette of a horse.
Container	Large bucket (5-gallon size recommended) or a tall plastic tub.	Holds the trapping liquid and catches flies.
Harness/Support	Rope, chain, or strong wire.	To hang the ball above the container.
Trapping Liquid	Water, dish soap, and sometimes a small amount of attractant (like molasses or yeast).	Kills the flies once they enter the container.

Building the Hanging Ball Trap

This design is fantastic for effective outdoor fly traps for horses near gates or high-traffic areas.

Step 1: Prepare the Lure

Get your large, dark-colored ball. Black is best.
If your ball is light-colored, paint it a dull, matte black. Glossy surfaces can sometimes reflect light strangely, making them less attractive. Let the paint dry completely.

Step 2: Prepare the Collection Bucket

Take your large bucket. This will catch the flies.
Fill the bucket about one-third full with water.
Add a few drops of liquid dish soap. The soap breaks the surface tension of the water. When a fly lands on the water, it sinks instantly instead of floating, ensuring it drowns.

Step 3: Setting Up the Suspension System

You need to suspend the black ball so that its bottom hangs just a few inches (about 2 to 4 inches) above the water level in the bucket.
Use wire or rope to create a harness around the ball.
Securely attach the harness to a tree branch, a tall fence post, or a purpose-built stand so the ball hangs still but is slightly exposed to the sun (heat helps).

Step 4: Placement and Maintenance

Place this trap in open sunny areas where flies congregate, usually 10 to 30 feet away from where your horses are standing. Flies see the black ball, fly toward it, circle it, and then drop down into the soap water below.

Empty the bucket and refresh the soapy water every few days, especially after a heavy fly season.

Method 2: The Plastic Bottle Trap (The Cheap and Easy DIY Option)

This is a classic DIY horse fly trap. It uses a 2-liter soda bottle to create a one-way entry system. It is very cheap and easy to assemble, making it a great option for building a stable fly trap where you need several units.

Materials Needed

One clean, clear 2-liter plastic soda bottle.
Utility knife or sharp scissors.
Wire or string for hanging.
Attractant bait (see lure ideas below).
Water and a little dish soap.

Construction Steps

Step 1: Cutting the Bottle

Carefully cut the plastic bottle in half, just below where the neck starts to curve outward (about one-third of the way down from the top). You will have a top section (the funnel/mouthpiece) and a bottom section (the container).

Step 2: Creating the Funnel

Remove the cap from the top section.
Flip the top section upside down so the mouthpiece points down into the bottom section like a funnel.
Secure the two halves together. You can use strong tape around the seam, or poke small holes around the edges and tie them together with string or wire. Make sure the connection is snug; you don’t want large gaps where flies can escape.

Step 3: Adding the Lure

The success of this trap relies heavily on the bait inside.

Effective Lures for Biting Flies:

Yeast and Sugar: Mix about 1 tablespoon of active dry yeast, 1/4 cup of sugar, and 1 cup of warm water. Stir until the sugar dissolves. This mixture ferments and produces $\text{CO}_2$, which mimics a host animal.
Meat/Fish Scraps: Flies are attracted to the smell of decaying protein. Place a small piece of raw meat or fish scraps (in a small, tied-off mesh bag or old sock) near the bottom of the container. Note: This option is messier and can smell bad up close.
Molasses Water: Mix dark molasses with water until it is thin enough to pour easily.

Pour your chosen attractant mixture into the bottom reservoir, covering the funnel opening slightly but leaving space for flies to enter. Add a few drops of dish soap to the liquid.

Step 4: Placement

Hang the trap in the sun. Flies fly in through the wide mouth of the funnel, drawn by the bait. Once inside, they circle the bottle, trying to find the way out. They eventually tire and fall into the soapy liquid.

Method 3: The Stable Fly Trap (Focusing on Ground-Level Pests)

Stable flies often bite lower down, near the legs and lower bodies of horses. A specialized ground trap can target these pests. This also works well as a building a stable fly trap solution inside barns or loafing sheds.

Key Differences

Stable flies prefer landing on dark surfaces and biting, rather than just hovering like horse flies. This trap uses a surface attraction combined with a collection chamber.

Materials

A shallow, dark-colored tray or pan (like a dark boot tray or shallow litter pan).
A slow-release attractant or a heat source.
Clear plastic sheeting or cling wrap.
Tape.

Construction

Prepare the Surface: Place the dark tray on the ground in an area where stable flies are a problem.
Apply Attractant (Optional but Helpful): You can lightly coat the bottom of the tray with a very thin film of Vaseline mixed with a small amount of brewer’s yeast. This gives them something to land on.
Create the Dome: Cover the entire tray securely with clear plastic wrap or sheeting, taping the edges firmly to the tray rim. This traps the air and moisture.
The Entry Point: Poke several small holes (just big enough for a fly) near the center of the plastic dome.
The Heat Element (Advanced): For maximum effect, some people place a dark-colored, warm object (like a water jug painted black and filled with hot water) under the clear plastic dome, positioned over the tray. The heat attracts the flies upward toward the small entry holes.

Flies smell the bait, crawl to the surface, find the small holes, enter the dome, and get trapped under the plastic film. They cannot find the tiny holes again to escape.

Enhancing Your Traps: Lures and Attractants

No matter which best horse fly trap design you choose, success hinges on what you use to lure them in. While heat and $\text{CO}_2$ are natural lures, we can boost this effect.

Liquid Lure Options (For Bottle Traps)

Attractant	Preparation Note	Effectiveness
Yeast/Sugar Water	Must be fresh. Produces $\text{CO}_2$ gas.	High, especially good for horse flies.
Fish Sauce/Water	Use strong-smelling fish sauce diluted heavily with water.	Very strong odor, attracts many species of flies.
Rotting Fruit	Banana peels or old apple cores soaked in water.	Natural fermentation attracts pests.
Commercial Lures	Pre-made fly attractant packets can be bought online.	Very reliable, but adds to the cost.

Enhancing Visual Attraction

If you are using a DIY trap, remember color is key. Flies are drawn to the contrast of a dark object against a light background.

If you use a clear bottle trap, place it against a white or light-colored wall or fence.
If using the hanging ball method, ensure the ball is matte black and unobstructed by excessive foliage.

These visual and scent cues work together to create powerful effective outdoor fly traps for horses that draw pests away from the actual animals.

Placement Strategies for Maximum Impact

Where you place your traps is as important as how you build them. You want to intercept the flies before they reach your horses.

Zone Defense

Think about the flight path of the flies. They usually emerge from shady, damp areas (like wooded edges or compost piles) and fly toward sunny areas where horses congregate.

Perimeter Traps: Place traps 15 to 50 feet away from the main horse area (paddocks, run-ins). This diverts the initial wave of flies.
Sunny Spots: Flies prefer warm, sunny locations to fly and hunt. Place traps in open areas that receive several hours of direct sunlight.
Avoid Overcrowding: If you have several traps, spread them out. Placing too many traps close together can sometimes confuse the flies, making them less effective than a single, well-placed trap.

This strategic approach maximizes the use of your homemade solutions, offering significant relief compared to relying solely on homemade horse fly repellent sprays, which require constant reapplication.

Maintenance and Safety Considerations

Even cheap traps need care. Neglecting maintenance reduces effectiveness and can create new problems.

Keeping Traps Working Well

Regular Liquid Refresh: For any trap using liquid, change the water and soap solution every 3 to 5 days. If the liquid evaporates or gets too full of drowned flies, the trap stops working.
Re-baiting: If you use yeast or fruit, replace the bait mixture weekly, as the yeast runs out of sugar or the fruit decomposes completely.
Check for Leaks: Inspect your bottle traps for cracks or loose seams. Flies are masters at finding small exits.

Safety for Livestock

While these traps are designed to attract flies away from horses, you must ensure the trap itself poses no danger.

Placement Height: Make sure hanging traps (like the ball trap) are hung high enough that curious horses cannot easily knock them down or step into the collection bucket. Falling into a bucket of soapy water or decaying bait is unsafe for a horse.
Non-Toxic Materials: Stick to household items like soap, water, sugar, and yeast. Avoid any harsh chemicals or strong insecticides in your homemade bait. If using meat scraps, ensure they are contained so horses cannot access and eat them.

These traps offer a great method for natural horse fly control without introducing chemicals into the environment where your animals graze.

Building a Stable Fly Trap: A Note on Materials Durability

When building a stable fly trap or any outdoor trap, the materials must withstand weather.

UV Resistance: Clear plastic bottles will eventually break down in strong sunlight. Inspect clear traps regularly. You might need to replace them seasonally.
Paint Choice: If painting your lure ball, use exterior-grade or outdoor spray paint. Interior paint will wash off quickly in the rain.
Rust Prevention: If using metal components (like wire hangers), consider coating them with clear sealant or spray paint to prevent rust, which can weaken the structure.

Comprehending Fly Trap Effectiveness vs. Sprays

Many horse owners rely on chemical fly sprays. While sprays are excellent for immediate relief during riding or grooming, they offer limited area protection. A good, effective outdoor fly trap for horses works 24/7, reducing the overall local fly population.

Feature	Chemical Spray	DIY Trap
Cost	High, ongoing purchase.	Very low, initial material cost.
Duration	Hours, requires reapplication.	Continuous, long-term population reduction.
Environmental Impact	Chemical residue on animals/pasture.	Minimal, uses common household items.
Target	Flies currently on the horse.	Flies in the general vicinity.

For best results, use traps for population control and use sprays only when direct contact or immediate defense is necessary.

Frequently Asked Questions (FAQ)

Q1: How quickly will I see results with a DIY horse fly trap?

You should see flies captured within 24 to 48 hours, especially on warm, sunny days. However, these traps work by reducing the local population over time. It might take a week or two of consistent trapping before you notice a significant, sustained reduction in fly activity around your horses.

Q2: Can I use a regular house fly trap design for horse flies?

Not usually effectively. House fly traps often use sweet baits that attract filth flies (like house flies and blow flies). Horse flies are primarily attracted by visual cues (dark color, silhouette) and heat/$\text{CO}_2$. If you use a standard house fly trap, you might catch some non-biting flies, but you won’t significantly reduce the biting horse fly population unless you incorporate the dark color/heat element.

Q3: What is the best attractant for attracting and trapping horse flies specifically?

The visual cue of a large, dark (preferably black), moving or stationary ball is often the most important factor for horse flies. Combine that with a weak $\text{CO}_2$ source, like a yeast and sugar mixture, for the best results in a DIY horse fly trap.

Q4: Should I place the trap near the water trough or manure pile?

Avoid placing the traps directly next to water sources or manure piles if possible. While flies breed there, placing the trap too close might attract other nuisance pests or make the trap area generally unpleasant due to the smell of decay, potentially driving horses away from the area you are trying to protect. Aim for the sunny resting/grazing areas first.

Q5: Are there any specific colors that repel flies instead of attracting them?

Yes. Light colors like white, light yellow, or very light green tend to be less attractive to biting flies compared to dark blues, reds, or black. If you are looking for a homemade horse fly repellent effect on your horse’s blanket or tack, lighter colors are sometimes preferred, though physical barriers are much more reliable repellents.