Horse Flies

Flies and biting insects are not only an annoyance, but they are also a health risk for your horse. There are a large number of diseases which can be transmitted to horses by biting insects, so protecting your horse from them is the best way to avoid such illnesses. 

Furthermore, like people, horses under stress tend to be less healthy in general and have less resistance to certain diseases. Although not all stressed horses will get sick, a horse under stress is more likely to get ill than one which isn't. Providing protection from biting insects removes an important source of stress and discomfort for horses.

Fortunately, there are a wide range of solutions. Here are the top 10:

  • Fly Repellents. Every horse supply store will have a variety of chemical sprays. These vary in cost and effectiveness, with the best providing up to a week's protection from a single application. In addition to the chemical solution, one can made organic (natural) sprays using scented oils. See horse fly repellents for details.   
  • Fly Sheets & Masks. These cover the most vulnerable parts of the horse, protecting it from bites. Although these can be expensive to buy, they can quickly pay for themselves by reducing or eliminating the amount of fly repellent you need to buy. For a discussion of the various options, see Fly Sheets & Masks.
  • Night Pasturing. Many horse owners allow their horses to graze during the day, but bring them into the stables at night. However, most horses have good night vision and could easily graze at night, when most types of biting insects are not around. Consequently, providing pasture during the night and shelter during the day is a natural solution.
  • Fly Parasites. There are a number of parasites which attack and kill flies. These parasites are harmless to people and horses, as they live on flies. Establishing a colony in your manure heap is a natural way to control the fly population. See Predator Fly for details.
  • Feed Through Fly Control. This is an additive which one puts in the horses food, which prevents or reduces flies from breeding in the manure.
  • Curtains. Many types of flies will avoid enclosed areas. Covering stable doors with horse curtains (these are a specific product, not like the curtains in your house) will discourage certain types of flies (e.g. the horsefly, but not the housefly), while still allowing your horse to enter and leave easily.
  • Fly Traps. Within the stables, there are a range of fly traps, fly papers and electric fly killers. Make sure that you keep all of these out of the reach of horses. There are also fly traps which are designed to be put on the fields.
  • Sanitation. Flies are attracted to moist areas and are also attracted to the smell of horse unine and manure.
    • Keeping your stables clean and dry (muck out at least once per day) will help to keep the fly population down.
    • Dragging the field at least monthly will also spread out manure heaps, so that they will tend to dry out and be less suitable for breeding flies.
    • Ensure that your stables are well ventilated to minimise moisture and odours.
  • Muck Heap. If possible, it is preferable to locate the muck heaps away from stables and riding areas, as flies are attracted to these moist, smelly areas. One can reduce the number of flies breeding in the muck heap either by spreading the manure thinly (so that it dries up) or piling it so that natural decomposition generates too much heat for the fly larvae.
  • Stagnant Water. Many insects (e.g. mosquitos) breed in water, particularly stagnant water. If you have wet areas on your ground, consider draining them.

Effectiveness of Solutions

All the above solutions work well for some people, but none of them work for everyone. The choice of which approach is best for you and your horse depends on a number of factors. Following are a few examples:

  • Insect Type.The effectiveness depends on the type of insect. For example, fly sheets do not work with ticks, but are very effective with horseflies. Likewise, draining stagnant water is effective for mosquitos but of limited value for reducing horseflies.
  • Your Horse. Some horses will refuse to wear a fly mask. Others will refuse certain natural fly repellents (e.g. garlic, vinegar water).
  • Your circumstances. individual circumstances can make a big difference. For example, if there are a large number of cows pastured around you, fly control will be much more difficult.
  • Implementation. Any of the solutions can be incorrectly implemented, decreasing their effectiveness. For example, fly parasites need to be provided with a suitable environment, or they will die and consequently be ineffective.
  • Your Time and Budget. Some solutions are expensive timewise (e.g. moving the muck heap further away) while others can be expensive financially. The choice of the best solution depends in part on your resources.

Due to these variables, each solution has its proponents who find it extremely effective and at the same time opponents who consider it worthless. However, when implemented correctly and in appropriate circumstances, each of these solutions can be effective. It is a matter of choosing which approach or approaches works best for you and your horse.

More Solutions

Above are the top 10 solutions for protecting your horse from flies and biting insects. Other solutions worth considering are:

  • Encourage Bats. Only some insects fly at night, but bats can really help to reduce the population of these. Providing suitable accommodation can result in a useful bat colony on your property. However, check about any legal implications; in particular you should be aware that in some areas bats are protected so once a bat colony establishes itself on your property it may be illegal to remove or modify their accommodation thereafter.
  • Encourage Birds. Some birds (e.g. swifts) feed on insects. Encouraging them (e.g. by providing bird houses of the appropriate size and shape) can help reduce daytime insects.
  • Air Currents. Many insects dislike air currents. Pasturing your horse in breezy areas can provide them with natural protection. Some people also install fans in stables to provide air currents.
  • Lights. Lights attract certain insects, such as mosquitos. By turning off or turning down lights at night, you can avoid attracting these insects.
  • Insecticides. There are a range of insecticides which one can spay on stable walls, or in the stable air (known as 'misters') or on muck heaps (to kill flies in the larval stage). However, there are a number of potential health concerns associated with these products, both for horses and people.