Horse Flies: Identify Them | Find Them | Get Rid Of Them

by | Flies, Insects

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If there are big flies around your home or yard that can bite, you probably have horse flies.

Horse flies are large flies with a gray or black body, shiny green or purple eyes, and short antennae. In summer, female horse flies bite people and animals to feed on their blood. They must do this before they can lay eggs. Male horse flies eat flower nectar and are not dangerous.

In this article you’ll find out:

  • How to identify horse flies
  • Why horse flies are called “horse flies”
  • Where horse flies come from
  • Things that attract horse flies
  • Are horse flies dangerous?
  • How to get rid of horse flies

How to identify horse flies

Photo of a horse fly with labels to identify a horse fly
To identify a horse fly, look for purple or green eyes, short antennae, a large, wide body, and 2 wings with shades of brown or gray.

The following table gives a list of characteristics on what to look for to identify a horse fly:

Known as – Horse fly
– Breeze fly
– March fly (Australia and UK)
Color – Usually gray, black, or brown
– Some are multicolored and have patterns on their body with yellow, green, or blue
Average length0.2 – 1 inch (5 – 25 mm)
Description – Horse flies are medium to large in size, with a wide body
– Head and thorax have short hairs
– Big green or purple eyes
– Short antennae
– 6 legs
– 2 transparent or cloudy wings, with shades of brown or gray
Flight patterns – Some species make a loud buzzing sound when flying and others are silent
– Strong, lively fliers
– Fast fliers, with some males flying 90 miles/hour (145 km/h) to get to a female to mate with
Attracted to / Where to find horse flies  Look for horse flies:
– Near horses, livestock, and other large animals
– Close to water, wet areas, and swimming pools  
Eggs – Females lay up to 1 000 eggs at a time on rocks and plants near water
– Worm-like maggots hatch from these eggs. They are usually white but can also be brown
Breed – Usually breed outdoors
– After hatching, maggots drop into the water or moist ground below
Eat  Young horse flies (larvae / maggots) eat:
– Each other
– Worms
– Insect larvae
– Invertebrate animals, like insects, spiders, and shrimp

Adults eat:
– Plant nectar and secretions
– Females bite animals and humans to eat their blood
Most activeDuring the day

Why horse flies are called “horse flies”

Horse flies are called horse flies because they love to annoy and eat the blood of horses, along with other large animals such as livestock, camels, and deer. Horse flies often live near these animals and bite them on warm, summer days.

But horse flies don’t just bite horses and large animals. Horse flies have also been seen biting birds, small mammals, lizards, and animals that have just died (along with blow flies).

Where horse flies come from

Horse flies breed in water or moist areas, including swamps, ponds, streams, swimming pools, wet soil, and humid woodland and forest areas. You will usually see more horse flies in summer (July and August), when they come out to mate and the females look for blood to eat so they can lay eggs.

Things that attract horse flies

Horse flies are attracted to water; warm, sunny areas; the color blue; and animals or humans to bite. When looking for a victim to attack, female horse flies are drawn to body movement (though they will suck on animals that died recently), the carbon dioxide their prey breathes out, and body heat.

Click here for a list of all the ways flies might be getting into your house.

Are horse flies dangerous?

Female horse flies chase and give painful bites to animals and people because they need to eat blood before laying eggs. The flies usually bite animals on their legs or body. Horse flies bite people on their ankles, legs, backs of knees, back of the neck, and wrists. Horse flies cannot sting.

When a horse fly bites several animals after each other, it can transfer diseases between the animals.

In people, horse fly bites often leave a patch of raised, red skin that stays sore for a day. Some people are allergic to horse fly bites and get dizzy or swell up after a bite. Horse flies don’t spread diseases from person to person, but their bites can get infected and turn into painful blisters.

How to get rid of horse flies

Horse flies are nasty pests but there are ways to minimize populations or get rid of horse flies in your home or on your property. Below is a list of recommended methods and products from Amazon that you can try:

Cool things down: Horse flies function best in warm, humid conditions where there is no wind.

To stop horse flies from coming or staying in your house, keep your house as cool as possible. Keep your air conditioner running, especially during the hot summer months. Have fans blowing directly at all open windows and doors, to stop horse flies from flying in.

Dry out your yard: Horse flies lay their eggs in water or near water and damp areas. Remove all water sources from your yard, cover and seal your swimming pool as best you can, and water your grass and plants as little as possible.

If you need to water, give long, heavy waterings in the evening just before sunset, when horse flies aren’t active, then leave the area to dry out as much as possible before watering again.

Stop horse flies from getting inside: Seal any cracks or openings in your roof or walls, and repair fly screens on the door and windows. If you like leaving your doors and windows open, and you don’t have any fly screens, hang one of these magnetic screen doors or magnetic screen windows to stop horse flies from coming in.

Release fly eaters: These fly exterminators eat horse flies (along with house flies and filth flies). Simply release them when horse flies are active in your area and let Natures Good Guys take care of the rest.

No chemicals, poisons, or maintenance required, and they’re harmless to pets, humans, birds, and other wildlife.

Use flowers to kill and repel horse flies: This botanical fly spray is made from chrysanthemums and other natural ingredients. The spray kills and repels horse flies along with many other pests, and it’s safe to use on dogs, cats, and horses.

If horse flies have infested your pool area, spray this product around the area to get rid of them. Just make sure it doesn’t come into contact with children and can’t be licked or swallowed by pets.

Trap flies with their favorite color: Horse flies are attracted to the color blue, which makes these blue disposable fly traps perfect to hang outdoors away from your windows and doors as there is a smell from the bait.

Horse flies are attracted to the trap’s color and smell, and then they get trapped inside and drown. When a trap is full, just twist the top closed and throw it away.

Catch horse flies with big sticky traps: Horse flies are large and need a good-sized sticky trap to catch them, just like these bug ball starter kits.

You can catch and kill horse flies with 2 or 3 bug balls per acre, without using any poisons or chemicals.

Bug balls are odorless and trap horse flies when they get stuck to the sticky coating on the heavy-duty, PVC balls.

I'm Monique. I love gardening and spending time in my backyard growing things. Here's where I share what I know about backyard pests and what to do about them, so you can enjoy your yard too.

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Monique loves gardening and spending time in her backyard, where she grows flowers, succulents, herbs, fruits, and vegetables.

Monique spends a lot of time researching how to protect her backyard from harmful pests and trying to attract beneficial insects and animals.

She shares everything that she learns and tests here at Backyard Pests.


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