RSS Feed
Email this article
Printer friendly page

Ask Rick A Question

Horse Fly

Summary: Horse flies are pests that pose a threat to humans and animals because they transmit diseases. The Horse fly serves almost no benefit to humans.

There are numerous types of horse flies including the Striped horse fly, the Greenhead, the Black horse fly, the Western Black horse fly and many others. For the sake of those of you having come to this website for immediate relief, I'm going to get right down to business. You probably want to know what just bit you, do you need to do anything about it and how can you avoid being bitten by that “thing” again.

A typical horse fly is as big, if not bigger, than the average house fly. It can grow up to one and one-quarter inches in length. That is a major-sized fly. Not quite big enough to carry off your dog, but certainly large enough to get your full attention. The horse fly's most distinguishing physical characteristic is its three sets of antennae. They also have two sharp jaws used for biting, which you know firsthand.


Adult horse flies are very active in wet or marshy areas and they are attracted to warm, sunny climates and big moving objects like horses, of course. Female horse flies eat mammals' blood, while male horse flies eat sweet nectar, plant sap, and pollen. So, now you know it's the female that is trying to take a chunk out of your leg. The horse fly sticks its head into its prey and sucks out juice or blood using six different mouth parts to pierce the hide or skin of its prey with a razor-sharp bite. It's a moment you won't soon forget.

Female horse flies are pests because they bite humans and animals, often causing allergic reactions, such as wheezing, rashes, and hives. Because horse flies may feed on several different species of animals, they can carry diseases and pass them on as they bite new prey.

Fortunately, horse flies do not appear in most of the United States until the summer. However, they can be seen year-round in Florida. If you have a swimming pool in your backyard you should be on the lookout for horse flies. The bad news is that there are no simple solutions to keeping them away from your pool. To avoid them, it is best to go inside until they fly away. If you notice that there are several horse flies around your yard in the summertime, staying indoors during the day is the easiest approach to avoid them. (You will also avoid sunburn, too!) At night, horse flies do not pose a threat because they are not active after sundown. They are also less active on windy days.

Horse fly trap

It is extremely hard to control horse flies because their breeding grounds can be far away and bordering ponds, lakes and streams where pesticide use is difficult. If you have a small creek in your backyard that does not contain fish, you could consider draining it in order to take away horse fly breeding areas. You could wear a nylon head net or a mesh jacket all the time, but those netted safari hats look really stupid when you're grocery shopping, don't they? If you are gardening or mowing the lawn, wearing a hat, a long-sleeved shirt and pants (especially in light colors) will deter horse flies.

You can also use any insecticide spray labeled for use around plants and vegetables, of course, to spray bushes or shrubs near wet areas to help dissuade them. However, do not ever want to spray insecticide in ponds or creeks because it will kill fish in the blink of an eye.

If you notice horse flies around your yard, make sure to bring your dog, cat, or pet llama indoors until they fly away. The horse flies. Not the dog, cat or llama. Animals are susceptible to diseases carried from horse flies and the horse fly bites really hurt them, as well.

Here is the most creative solution to pesky horse flies. You can create a contraption to ensnare them. Take a table or stool and attach a dark colored medium sized ball to a rope that hangs underneath. Apply sheets of flypaper underneath the flat surface and around the rope. Horse flies will be attracted to the dark ball, especially if it is swinging. When they realize the ball provides no source of food for them, they will fly upwards and either get caught in the flypaper or the net. Or, you can buy the Horse Pal fly trap on line for about $230, plus shipping. It ain't magic, but it's better than nothing.

Click here to watch my short video on how to control flies.

Ask Rick A Question


24 Jul 2012, 03:14
In my neighborhood, there is a vacant house that has much mold and water damage, and old rotting tree limbs covered by much shade and house full of dog crap other neighbors tell us. Could any of these be a source for the horse flies?
Ask the Exterminator
24 Jul 2012, 17:04
It is certainly a source for some type of flies.
Josh G
09 Aug 2012, 10:49
Hello, we have noticed 10 to 15 horse flies in our house in the past few days. They seem very dazed and lethargic and are easy to kill. None the less concerning. Do you have any idea where they could be coming from?
Tanya Aguilar
20 Aug 2012, 21:42
I have same problem as josh g over the past few days we have killed several daily all in the same area of the house the corner of family room, lethargic big black flys.
What could the source be and how do we get rid of them the just stick to the corners of the walls weird...
28 Aug 2012, 22:33
I was wondering what the "normal" lifespan of the horsefly is? I just recently became infested with them in my basement, looked them up all over the internet and am nearly certain that is what they are. There are numerous farms within close proximity of my home. I would like to get the rat glue traps because I don't think the regular rolls of fly glue will do the trick lol. Thank you very much for your time.
Island Girl
30 Aug 2012, 14:55
We live on the Chesapeake bay and every year these scary looking pests come out in august, I can tell you they are attracted to carbon dioxide from your car. If you shut your car off and wait they will dissipate. they buzz us when we go outside but in 3 summers we have yet to have one land on us or bite, they seem to be very skittish and clumsy.
11 Sep 2012, 11:21
I cat figure out why my Great Pyrnees and I keep getting "swarmed by them and my mom, dad, and two black dogs do not. It never fails 5 minutes out walking the dogs and my Pyr and I are being "attacked" and the other ones are not and when I try to do work outside or tend to our chickens and pig I get them flying around me and if I don't rush inside im bitten. Why are they attacked to us?? I thought it might be my soap or shampoo but I use the same as my folks and the Pyr uses the same as the other dogs?? Please ANY ideas would be SOO HELPFUL! I'm going insane and my work is piling up.
04 Jul 2013, 22:35
Having small kids around a lake or pond a good way to deter horse flies is by applying baby oil. Horse flies will land but not bite they just don't like baby oil.
06 Jul 2013, 12:19
folks, just because it is a "huge fly" does not make it a horse fly. those flies swarming your windows are newly hatched HOUSE flies, they will either go outside or die within a few days. If they were horse flies they would not be buzzing your windows, they would be flying around your head trying to feed off from you.
29 Aug 2013, 11:10
Several years ago, I saw what I thought was a humming bird flying around our horse. I went outside to look and it was the biggest horsefly I'd ever seen. As God is my witness, it was over an inch and a half long. When it landed on my horse's rump,I hit it quickly with a rolled up newspaper, stunning it. (My horse was a little startled but didn't move). I picked it up and immediately put it in a jar and took to to my local feed store to show the guys there. They too admitted that they had never seen any so big. It was totally black. Thankfully, I never say any more that size, tho they get pretty big here in Michigan.
03 Sep 2013, 08:13
The last week in August this year,2013, I was walking on a small island on Lake Lanier,Georgia. I felt a sharp pain in my lower leg. I looked down to see a giant dark brown insect, which I have concluded through pictures was a black horse fly, on my leg. I instantly hit it off. It was probably 1 1/4 inches long and fat. It reminded me of a chunk of pine bark. Within 15 minutes I was covered in hives, my scalp was so itchy and my lower lip and eye lids were swollen. The pain from the site of the bite radiated down my leg. Iever had breathing problems. I had antibiotics on hand at home so when it got really red and hot , I started to take them. It has been over 1 week and my ankle and foot below the bite is still itchy and swollen. Ironically, I did not use DEET that day like I usually do.
pamela venn
09 Sep 2013, 20:08
we have recently been infested with large flies dive bombing our truck . last week we found several mounds of light colored balls covered with black and white horizontally stripped worms near the fence line along our drive way. Do you think the worms and flies are connected
steven gass
21 Jun 2014, 10:11
i just moved to a new apt. and i notice that their are big flies in my bath room their was about 8 or 9 around the window what can i do to get rid of them thank you steven
08 Jul 2014, 19:04
hi hose flys always try to bite me at the pool at camp how do I prevent that from happing?
15 Jun 2015, 14:46
Is there anything a GOLFER can used to repel horseflies?
30 Jun 2015, 10:19
And remember. ...when you go in for the kill... slap them from behind and down. If you slap from the head they will simply fly away. Horse flies launch backwards.
Notify me about new comments on this page
Hide my email
The box below is for visitor comments! Questions posted in this box may not be answered by Ask the Exterminator. For quickest response click on the "Ask the Exterminator a Question" link at top of this page.
Security Image:



More Articles Like This

  • Pipevine Swallowtail Caterpillar
  • Robber Fly
  • Get Rid of Gnats
  • Fly Control
  • Blowfly
  • Black Flies
  • Sand Flies
  • House Flies
  • Garbage Maggots

  • Categories: