5 Ways to Control the Flies

Contributed by: Valerie Mellema

I was reading the Southern Living blog the other day by the Grumpy Gardner about the never-ending fight against gnats in the summer. Most of it was sarcasm, as there’s really not a whole lot you can do about gnats, but the best line of the entire article was “First–and this is so obvious, I’m embarrassed to write it–never go outside in summer." And that’s kind of how I feel about flies, except not going outside isn’t really an option for our horses and all we can do is fight the best fight we can to control them. Fortunately, there are a few tools that we can utilize to try and control them as much as possible.

Automatic Barn Fly Spray Systems

When I was a teenager I worked in a Hunter/Jumper barn that had an automatic fly spray system. The flies in the barn were pretty much non-existent, you just had to take cover when cleaning stalls or you’d feel like you just got gassed! Fortunately, it made a ticking sound and you could step out real quick before the spray came out.

These systems are set up a lot like a misting system with heads over each stall. It is fed by a big drum that contains the fly spray and it can be programmed to go off every so often. These systems are very effective and I would say well-worth the cost, particularly if you have horses in the barn throughout the day.

There are also smaller versions of these available that are in a dispenser similar to an automatic air freshener dispenser.

Fly Predators

These are actually little wasps that kill flies! They are active at night, so you’ll hardly notice they are there. They actually breed and live off of the fly larvae, so they kill the flies before they even really get started. Even though they are wasps, they don’t sting or bite people or animals.

Fly Control Blocks

These are great for horses that stay out to pasture. Similar to a salt block, they will eat on the block and the non-toxic larvicide will get into their system. The larvicide in the block will kill the larva as flies lay it in manure. It is recommended to start using the blocks about a month before fly season really hits.

Fly Bags

These are good for the perimeter of your farm. Keep in mind that you do want them away from wherever you spend the most of your time at the barn. They stink and they attract flies. If you keep them on the perimeter, the flies will be attracted away from where you are! They will need changed out periodically as they fill up. There are several options available. They are also available for yellow jackets and wasps.

Fly Spray

Fly spray is a staple around the barn. There are a wide variety of options available on the market as well. You may find that you have to rotate through brands as some may not be as effective as others at different times during the season.


The main key to fly control is to keep the manure under control. Keep stalls clean and odor down. Spread manure in pastures thin and then just fight the good fight! Some horses may be very sensitive to flies as well, so fly sheets and masks may also need to be used. One note on fly sheets though is that they can be very hot for horses that are outdoors with minimal shade. Fans in stalls an also help discourage flies while also keeping your stalled horses cool. 

Did you find this article helpful? How do you fight off the flies?

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Valerie Mellema & Mistic Gray

Valerie Mellema & Mistic Gray

Valerie Mellema is the owner of Gray Horse Publishing & Marketing.

She has been in the equine industry for over 25 years and is a published author of multiple horse care books. She is also the owner of Mellema Thoroughbreds, a thoroughbred breeding farm. She shows her OTTB, Mistic Gray, in hunter/jumpers.

You can follow her on Facebook and Instagram.