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
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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.
Comments
DRP
09 Jun 2010, 13:42
I have a light grey horse and a sorrel paint pony. The horseflies seem to
attack the grey much more than the paint. He looks like he's been shot
with bird shot after an hour outside. I keep them inside most of the time.
I'll try turning them out after dark and see if that helps. thanks.
P. S. I have found NO fly spray that is effective at repelling them.
Ask the Exterminator
09 Jun 2010, 13:51
Have you tried Wipe Fly Protectant or DuraGuard or UltraShield? Those are
some of the treatments for horse flies that I found on the web.
chuck neel
11 Jun 2010, 20:52
i have been looking for info on this for ever. thanks this is the best info
yet
Vicky
19 Jun 2010, 14:08
Most of us who have ever spent time at a pool or lake have experienced the
joy of a stinging horsefly bite. My 9 year old son had his first encounter
today at the lake. We spotted this HUGE black insect on his hand, at first
I thought it was a wasp, he freaked out and said "it's hurting me!" and I
told him to put his hand in the water, which he did, and the thing flew
off. But then it was buzzing around our heads, and I just splashed and
splashed water into the air until it left. My poor son was left with a big
red welt on his hand. Flies suck!!!
ruby
13 Jul 2010, 10:37
i use ant and roach spray ,the horse flies dropped within seconds,
swerrling on the floor , i had to sqush them , though , but it worked !
brandon
23 Jul 2010, 17:57
I dont live anywhere near a pon or stream, ii dont live near a farm, no one
around here owns horses, and they still bother me outside a lot. Whenever i
go out it sucks because i know im gonna be coming back inside with a rask
from a horse fly bite.
Ask the Exterminator
24 Jul 2010, 11:59
Even if you don't live near a pond or stream, the presence of horse flies
means there are breeding sites not too far away. They wouldn't be there,
otherwise.
angela
19 Sep 2010, 16:43
I noticed horse flies in my livingroom window yesterday.... i swatted them
all and some of them appeared to die and come back to life... I killed them
by stepping on them.there were 22 in all. Today i went into the living room
and there are just as many new ones!!
Although there is a lake in the rear of my home, ive never seen them
before. and i dont understand how or why they have chosen now to come into
my home, or why they choose to congregate only in the living room window.
Ask the Exterminator
19 Sep 2010, 17:08
Horse flies breed along the moist soil adjacent to the lake. Not sure why
you suddenly have horse flies emerging inside your home unless there is a
crawl space under the house that could have a moist environment.
Inside, the flies will move towards the light of an exterior window to try
to escape.
Paul
08 Oct 2010, 21:50
I do not have a pond nor pool, but I am having the same thing happen to me.
Suddenly I had 18 flies that I killed yesterday in windows around the
house and today I had about 9. These are striped horse flies.
I have a couple questions:
1) since they come back almost immediately, do you think they are
re-populating in the house?
2) Should I be concerned about a dead animal in or around the house?
3) Most importantly, what can I do to get rid of them?
Ask the Exterminator
09 Oct 2010, 08:04
Ponds, marshes, streams, lakes. That's where you find horse flies breeding.
Horse barns, animal pens, too. They don't lay eggs inside homes. Moist,
decaying matter is the source. High water content. Have you had them
professionally identified? Are you sure they are, in fact, horse flies?
(You may continue this conversation by clicking on the "Ask the
Exterminator a Question" button at the top of this page.)
Rita
10 Oct 2010, 08:55
I AM GOING NUTS TRING TO FIND THE SOURCE OF THESE MONSTER FLIES.COULD THEY
BE COMING THROUGH THE AIR VENTS IN MY HOME? THEY KEEP MULTIPLYING,I HAVE
KILLED AT LEAST 30 IN 2 DAYS.ALL WINDOWS ARE DOWN,THERE IS NO CRAWL
SPACE,MY HOME IS VERY CLEAN,I JUST DON'T KNOW WHERE THEY ARE COMING
FROM.PLEASE HELP!!
jean Pennington
26 Mar 2011, 16:38
i am having the same problem with striped horse flies
in my house. i live no where near a pond or any
water. i do have a dog my house is clean but these
flies are driving me nust
Ask the Exterminator
01 Apr 2011, 16:27
Until you get the "horse" flies properly identified, you are only guessing.
Knowing the exact fly species will tell you where they are breeding and
that will lead to their control. Collect a few flies and get them
identified by a pro.
Jessi
09 Apr 2011, 14:06
Hi. My neighbor keeps a horse in a shed in his back yard. I just recently
noticed the horse and my husband says that they just brought it not too
long ago. Well, Every since that brought it I am having constant problems
with big horse flies coming into my house. I kill 2 and 6 come back. Is
there anything i can do to keep them out of my house. I have children and
it freaks me out because i don't know if those things ever land on there
toys.
Ask the Exterminator
10 Apr 2011, 09:04
You are going to have to work with your neighbor on this problem. The horse
flies are coming from the barn. The source must be treated.
jeff
14 Jul 2011, 15:52
Yesterday i had a wonderful day on the water in gloucester Mass with a good
friend boating. Within an hour I had become attacked en masse but a group
of green headed flies with a vicious bite. I had blood running down my legs
within minutes. The day after My legs are covered with horrible welts that
itch terribly and my legs swelled up. WHATS THE CURE?
Ask the Exterminator
14 Jul 2011, 18:03
You don't call an exterminator when you have a health problem. You seek a
doctor.
madie
18 Jul 2011, 14:37
for the past 2 days we've been fighting horseflies(approx 1" in length, red
eyes, white stripes on their back). they're practically swarming our
bathroom, all on the window trying to get out (we have a bathroom with a
window in the actual bathtub area). we have an idea as to where they're
coming from - but we have no outside water anywhere near us. we live over
15 miles from the river, no lakes, no creeks, no water near us - so i'm not
sure if my idea is correct.
we're doing work on our house - have had the under house crawlspace open
for a couple days (just while work being done) to access the plumbing
(conventional foundation). we also have a rotten window in our bathroom and
had an insurance adjuster come out to look at it during this plumbing
process and he opened the window to look at it, but shut it back. now the
flies are EVERYWHERE.
could they have maybe laid eggs under our house (no leaks tho) or in the
rotten window sill maybe?
if so, the under house crawlspace is closed so i'm hoping they'll go away.
but if it's the window, short of replacing the window (which will happen,
but not right away) how can we get rid of these suckers?
please help. they just keep on coming.
Ask the Exterminator
18 Jul 2011, 16:26
Horse flies do not commonly infest homes, but regardless of the actual fly
species, their presence is due to a moisture source. It's where they breed.
So, find the moisture, eliminate it and you will be fly-free.
Chelso
22 Jul 2011, 00:09
Hi. For The Past 2 Weeks ive had a problem with horse flies we donnot have
a creek anywhere nor horses around but we do have a swimming pool. it has
bittin my nana 3 times 2 on her back and 1 on her stumoch and it terrifies
me to even go swimming at night do you think there is a solution please
help today it tried to attack me on my face and crept up on my sister but
we safely went into our house please reply soon!!!!!
Ask the Exterminator
22 Jul 2011, 09:02
Horse and deer flies are attracted to such things as movement, shiny
surfaces, carbon dioxide, and warmth. The swimming pool really draws them.
These flies are only active during the day.
Repellents such as DEET and Off can provide several hours of protection.
Light colored clothing may help in reducing their attacks.
Chelso
22 Jul 2011, 12:24
thanks so much.(:
James
22 Jul 2011, 14:00
Regarding the occasional fly around the pool area - I think we're all
becoming a bit too alarmed here. I am surrounded by horse farms, ponds and
streams and we have yearly cycles that differ, especially with the very
large black flies that come around once every 7 years. Almost every one of
them is about as stupid as you can get, simply relax and let them land you
you. Give them a few seconds to focus their attention on feeding, and whack
them with your hand. They take almost 8 seconds to actually bite.
Tina
26 Jul 2011, 00:59
I came home today around 7 in the evening & my car was attacked by what I
am thinking are both tabanus sudeicus & atratus. There was at the least
20-30 dive bombing my car & followed me back out of the driveway until I
got about a mile down the road. This happened a few times because I was to
afraid to get out of my car, until 9pm. I have never had an issue before &
I was wondering if these huge horse flies usually swarm like this, are
usually this agressive & if there was something I could do to prevent this
again? Im not going back outside until I know their gone. Please help, Im
terrified!!!
Ask the Exterminator
27 Jul 2011, 11:14
If you have a dark colored car (black or dark blue), the flies will be
attracted to it and fly at it. Nature of the beast.
Floyd
27 Jul 2011, 21:37
If ants can be killed at the nest by carrying back baking soda mixed with
sugar then maybe the male horsefly can be killed by mixing the baking soda
or something else into a sweet nectar they drink for food. If you eliminate
the male then you can eliminate the female. Or else mix poison into some
blood?
Jane
02 Aug 2011, 15:40
Is there anything that can be added to swimming pool water (besides the
usual chlorine) to discourage horse flies from congregating?
Also, I suspect that the horse flies in our basement are attracted by the
moist surface of the utility sink in the basement laundry room. If they
have laid eggs in the area of the sink, will a wipe with chlorox kill the
eggs? Thanks?
Ask the Exterminator
02 Aug 2011, 16:04
They don't breed inside. It's the reflection of the water that is
attracting them.
Tammy
09 Aug 2011, 16:33
I live next to a field where cows and sheep graze all day. The farmers
flood the fields with water. Is that where the horse flies that I get
inside my home coming from? Will that contraption with the ball and table
work for my ?ituation
Ask the Exterminator
09 Aug 2011, 16:37
That is exactly where the flies are coming from. The "contraption" will
help, but it does not eliminate the breeding grounds.
Tammy
09 Aug 2011, 18:19
Could you recomend any of your products that may help get rid of them, the
horse flies and house flies.
Ask the Exterminator
10 Aug 2011, 13:37
Removing the breeding areas is the most effective method. Horse flies breed
around lakes and ponds, so stopping them is nearly impossible. House flies
breed in any decomposing matter including piles of dead grass and leaves,
compost piles and in the bottoms of dirty garbage cans. It's a matter of
hunting for these locations. You can use a product like Maxforce Fly Spot
to control house flies, but the product is for outdoor use only. Here's a
link to the Maxforce product:
http://shop.asktheexterminator.com/flies/maxforce-fly-spot-bait-bottle.html
.
sean
06 Nov 2011, 00:48
excuse me, but im doing a project for school about horse flies, i have two
questions : 1. how long do they live and which months in florida, and how
can i capture one to take pictures