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By: Lori Underwood
Flies around the barn are more than just an annoyance; they can also be a risk to our horse’s health and welfare. Several diseases and conditions can be caused or spread by flies, such as equine infectious anemia, pigeon fever, summer sores, rain rot, and allergic dermatitis. In addition, horses who spend all day stomping and biting at flies, or fleeing frantically from one spot to another to avoid the swarms, can suffer from lameness, loss of appetite, loss of weight, decreased energy, and an overall unpleasant quality of life. Fending off flies can feel like a daunting task to farm owners, but there are many steps that can be taken to improve the situation significantly!
There are many different types of flies that are a problem for horse farms, but the ones we have the most control over as managers fall under the category of “filth flies”. Filth flies are flies who breed in areas that have moisture, warmth, and decaying organic matter. This category includes species such as house flies and stable flies, two of the more annoying types of flies we see around the barn. As their classification implies, filth flies thrive where cleanliness and management practices are poor. Under favorable conditions they are prolific breeders, with 2 flies able to produce as many as 2 million offspring in 12 weeks or less! Even small changes to our management routine can make a big difference in the number of flies our horses have to contend with.
Many areas of our barns can easily meet the ideal conditions of moist, warm, decaying organic material. Between manure, spilled feed, leaking hoses, wet areas around water troughs and buckets, left over hay, moist bedding material that gets packed under the edges of rubber mats, and plant material that is tall enough to block the sunlight from reaching the ground to dry it out, we inadvertently create some ideal housing for fly larvae to thrive!
How do you control flies in a horse barn?
The following steps will help you control flies in your horse barn, eliminating potential breeding grounds:
- Clean stalls daily, removing all manure and wet bedding. Remember to get around the edges of those mats and clean up all feed that has been spilled on the floor. It takes only a tiny amount of material for an adult fly to lay eggs in, so attention to detail is important.
- Clean paddocks of all uneaten hay and manure and ensure that your water trough is not leaking or being overfilled. Muddy areas, particularly those with ground in forage, are ideal breeding grounds.
- Keep pastures mowed so that sunlight can reach the ground and drag as often as possible to avoid a buildup of manure in piles that stay moist for a while.
- Keep the grass and plant growth near your barn to a minimum. Again, sunlight will do a lot of the work for you if you let it!
- Dispose of trash daily, and keep garbage cans clean, both inside and out.
- Make sure your grain is stored in closed containers, particularly any feeds that contain molasses or other moist additives. Clean up any spillage in the feed room immediately.
- Keep your manure pile as far from the barn as possible.
- Monitor your hoses for drips and leaks, and plan your hose usage for bathing, etc., so that wet areas created can dry thoroughly and quickly.
- Horse trailers are also a great breeding ground, so keep them cleaned out after each use, including under the mats!
- Make sure that receptacles that can hold water, such as unused buckets and feed tubs, wheelbarrows, etc., are stored inside or are upside down to keep them dry. This will help eliminate mosquito breeding areas as well!
Any Integrated Pest Management (IPM) plan begins with creating an environment that is less friendly to the breeding cycle of flies, and the above steps will go a long way towards decreasing the number of flies that breed on your property, but additional steps might be necessary. Another layer of the IPM system is blocking the access that flies have to the barn and the horses. Screening barn doors and windows can be a great help, but this is not always a practical step for many farms. A good way to eliminate some of the annoyance of flies is to add fans to the stalls, and/or the barn entryways. A good stall or barn fan can keep horses fly free and comfortable, but always use fans with “closed” motors, that are designed for dusty environments. Typical house fans have an “open” motor, which allows dust and debris into the motor, and are a leading cause of barn fires.
What keeps flies away from horses?
Fly Sprays
There are many different fly sprays on the market, some of which only repel the flies, and some that kill flies as well. Spraying horses liberally, and reapplying as horses sweat or get wet, can go a long way towards making horses more comfortable, as can fly sheets and masks. Hanging fly strips or traps in the barn areas can also have a dramatic impact.
Parasitoid Wasps
Another layer to an IPM program is biological in nature and can include steps such as introducing parasitoid wasps to your property. These tiny wasps, which do not sting, lay their eggs on filth fly pupae, and they consume the pupae as part of their development process. As the wasps continue to breed, and consume more and more of the pupal phase flies, they will gradually eliminate a large portion of the fly population.
Chemical Fly Control
As a final resort, using chemical means to kill flies is an option. From feed through products that pass through the horse’s digestive system without harm, but kill fly larvae in the manure, are an option, as is the use of larvicides and pesticides sprayed on the property. These more extreme measures should be implemented with caution, as resistance to these products is a growing concern, much like parasites increasing resistance to worming products. It is wise to exhaust other management options before resorting to chemical means, in order to maintain effectiveness to these products when all other options have been exhausted.
With a little effort and attention to management details, you should be able to reduce the fly population around your horse’s home dramatically, making horses and humans who share their space much more comfortable and fly free!