If you’ve had an unusually wet spring and temperatures are now ramping up, biting stable flies are coming! Below is the who, what, when, where, and why...and how to help reduce the impact.

Who’s going to be most likely to have problems with stable flies? 

Anyone who has received a lot of rain and has warming temperatures, especially if you have had flooding or standing water.

What exactly is coming?  

Biting Stable Flies are blood feeding flies that like to breed in manure, decaying vegetation, and other rotting organic matter.  Biting stable flies have a painful bite and most often bite on the legs and flanks of horses, causing them to stomp.  Females of these flies can lay up to 80 eggs at a time and lay 10-12 clutches in a lifetime. That means every female biting stable fly has the potential to produce nearly 1,000 offspring in her lifetime!

When is this population explosion of stable flies likely to happen?  

NOW!  If you’ve had a wet spring and have been starting to get hot during the day, you probably already have these leg biters.  If you don’t have them yet, they’re going to start soon.

Where are all these flies coming from?!  

Despite the name ‘Stable Fly,’ biting stable flies rarely breed in stables.  They do however like to breed anywhere that has manure or decaying vegetation.  Aside from manure and manure piles, there are many many other places biting stable flies can breed.  Some common areas you may have include: mower decks that haven’t been cleaned on lawn mowers, grass clippings, some types of organic mulch, hay chaff outside the edges of barns and outdoor pens, mossy/weedy edges of ponds (especially as the water begins to recede), boggy or marshy areas, compost, and many more.  

Why are things worse this year? 

Many of the areas mentioned above dry out before biting stable flies can complete their life cycle in normal years.  With all the extra rain, and in some areas flooding, ditches and drainage areas have more debris than usual, lawns may be thicker before being able to be mowed (so more and denser grass clippings), thin layers of hay chaff outside are staying damp longer, etc.  Also, biting stable flies are more likely to travel farther than house flies in their search for blood.  Often several miles or more. So, with breeding areas being more favorable to biting stable flies, more hungry adults are looking for your horses and even you to feed on. 

How can I reduce the impact?

#1 Sanitation, sanitation, sanitation!  Try and keep ditches clear of debris and draining well. Rake up grass clippings, dead weeds, hay chaff, and any other dead vegetative matter.  If things are staying damp, it’s better to have everything in one large pile to begin composting.  Composting releases heat that can help kill many of the fly eggs and larvae, leaving only the cool outer edges of the compost pile to be favorable to fly breeding.  If possible, turning the edges of this pile up to the top can prevent fly breeding completely. Try to keep weeds and other foliage cut back to reduce areas for flies to rest and to help sunlight reach more areas to dry things out.

#2 Add more Fly Predators to match the much higher number of fly larvae (maggots) that survive to the pupal (cocoons) stage.  This happens due to the moisture of manure and other rotting organic matter remaining in the 40%-60% range.  

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#3 Add traps. Biting Stable Flies are only caught with the Bite Free Stable fly trap from StarBar. This is the only commercial trap for biting stable flies on the market.  Bite Free traps should be placed low to the ground, preferably placing it at a height similar to your horse’s leg.  Remember, these flies like to feed on the lower legs of horses, people, and anything else warm blooded, so you want the trap at a height the flies normally feed.  These traps imitate animal body heat, which attracts the biting stable flies that then get stuck to the trap.   These traps do have a durable glue that will not wash away in rain or melt in heat; however, because of this make sure your horse cannot reach the trap (if placing outside of a fence, consider how far your horses tail reaches outside the fence).  Also, because this trap is clear, once flies start getting caught it may look like an easy meal to small birds.  To minimize the chance of birds getting caught on the trap, place the trap away from areas where small fledgling birds may be and away from any areas where birds are normally fed.  In addition, using an owl decoy or cheap rubber snake can also help deter birds from coming closer.

Watch our How to Use Fly Traps.

 #4 With flies coming in from off your property, you may also need to resort to fly spray this year. Our new Bye Bye Insects Fly Spray is the first primarily essential oil spray that matches the performance of the very best synthetic Pyrethroid sprays.  But unlike those, it can be used on yourself and your horses. It’s also effective for Mosquitoes. It smells nice too!  If house flies are getting in your home, you can spray Bye Bye Insects around the door frames to repel flies hanging out near there waiting to zoom in when the door opens.  Bye Bye Insects will stain light colored hair on horses, so we do not recommend use on white, gray, or pinto show horses or horses where staining is a problem.  The staining does wear off, but does not wash off.


This tremendously helpful blog was written by our rockstar entomologist, Jessica Starcevich! Thanks SO much Jess! You truly do rock!

House Flies are also going to be excessive for wetter than normal regions so check out specific for those pests as well! Click HERE!