Fly and Midge Control

Stable flies, horseflies  and face flies are a menace to your horse's health and well-being.  Stable flies, by far the most common, are the same size as a house fly but while house flies just feed on garbage and spread filth, stable flies (both males and females) suck the horse's blood. The stable fly feeds by inserting its proboscis (beak) through the skin and then sucking blood from its host. . It is a daytime feeder, with peak biting occurring during the early morning and late afternoon.Common feeding sites include the lower legs, flanks, belly, under the jaw, and at the junction of the neck and the chest.  When stable flies have finished feeding, they seek shelter to rest and digest.

The bite of a blood-sucking fly is painful and some horses have such a low fly tolerance that they can be driven into a snorting and striking frenzy . Even fairly tough horses, subjected to a large number of aggressive stable flies, might spend the entire day stomping alternate legs which can cause damaging concussion to legs, joints, and hooves, and result in loose shoes, and loss of weight and condition.

Stable flies breed in decaying organic matter.  Moist manure is a perfect medium.  The life cycle is 21 to 25 days from egg to adult.  A female often lays twenty batches of eggs during her thirty day life span.  Each batch contains between 40-80 eggs.  When the eggs hatch, the adult flies emerge ready to breed. The number of flies produced by one pair of adults and their offspring in thirty days is a staggering figure in the millions.That's why fly prevention is the most important line of defense in your war against flies. The variety of breeding sites, and the fact that the adults fly several miles to feed but spend little time on the host, make it difficult to manage stable flies.


  1. Your first line of defense is  TO PREVENT FLIES FROM BREEDING.
  2. For those flies that manage to breed, your second line of defense is TO PREVENT THE LARVAE FROM HATCHING.
  3. If some of the larvae succeed in hatching, your third line of defense is TO CAPTURE ADULTS FLIES IMMEDIATELY.
  4. To deal with flies that avoided the traps, your fourth line of defense is TO KILL THE REMAINING FLIES.
  5. For flies that escape your previous four efforts, your fifth line of defense is TO PROTECT YOUR HORSE.

Probably the first step in any kind of elimination program is the goal in preventing the next generation of flies from occurring. To inhibit breeding you will need to control the moisture in your stable as well as the manure. This translates into daily stable duty chores involving the removal of manure as well as uneaten feed. The manure should be spread very thinly to have it dry out quickly which will further destroy the habitat for fly larvae.

These steps notwithstanding, you will still have to deal with the flies that do manage to breed. Since some flies – mostly houseflies - lay their eggs in your horse’s stool, you may add feed-through products which will effectively impair the flies’ favorite breeding ground by sterilizing it, thus killing off any hatching larvae in the manure. The feed-through itself is non-toxic to the horse, but it will have a distinctive effect on the flies. It is imperative that every horse in your barn or pasture will eat this substance, since otherwise the flies will simply zero in on the untreated animals.

Other kinds of flies will prefer other living environments. For example, stable flies prefer to breed in manure that is combined with straw, but also in wet straw, grass clippings, moist soil, and even grain. Since these kinds of flies are hard to control, some horse aficionados have begin to utilize parasitoids, minute wasps which do not bother horses or people, yet effectively decimate the fly population by using the larvae as a food source. If you choose to go this route, you will need to ensure that the wasp population remains high to combat the flies, which generally means replenishing them. Also, everyone else in the area needs to be using this method if it is to be successful.

Whatever flies do manage to make it past those little wasps need to be captured with bag traps that are laced with a fly attractant and which will capture large number of these insects. These fly traps come in many varieties.

Last but not least in your attempt to control the fly population should be the use of insecticides. The goal of the entire fly management program is to have as few flies left to kill as possible. There are a wide variety of insecticides available; there are topical sprays, foggers, and also misters. Fly  bait will work on the insects that do not feed on blood, thus it will only work on house flies. Another important method of fly management is proper weed and vegetation control. Whatever insecticide you may decide to use, make absolutely certain that it is labeled for the use around horses, and that it is safe to use on bedding, inside stables, inside enclosed areas, or wherever you will plan to use it.

A final mode of control program involves repellants that are applied directly to your horse. These may take the forms of shampoos, lotions, and other kinds of applications that will bring the repellant in contact with the horse. Effectiveness of the repellant depends in large part on its staying power; the latter depends on its base substances. For example, oil based products may stay on longer than water based repellants, and so you will need to be aware how often you will need to reapply the substance.

Mechanical repellants include clip-on repellent strips that are attached to the bridle and fly masks.


Culicoides midges are widely distributed in South Africa. Larvae develop in moist soil rich in organic matter. Damp areas at the edges of ponds, swamps and manure lagoons are the more favored breeding sites. Several generations can be produced each year.

Adult stages rarely fly far from breeding sites. Most biting occurs at dusk with a secondary peak period of biting at dawn. Where conditions allow, breeding adult insects can be present and produce problems for months.


Control of larvae with insecticides is not possible due to their inaccessible breeding sites. However, some reduction of breeding is possible through cultural practices that modify larval habitat. This could include intermittently flooding and/or alternately thoroughly drying ponds that serve as breeding sites. Eliminating stagnant water rich in organic matter will help reduce breeding habitat.

Success of adult control is not likely and has not been demonstrated. Although these flies do not disperse great distances, adult biting midges can range widely. They tend to rest on tall grasses during the day. DEET is only marginally effective as a repellent although it seems to be the most effective repellant.

The adults are most abundant near productive breeding sites, but will disperse to mate and to feed. The mean distance for female flight is 2 km, less than half of that distance for males.

Additionally, because midges are so small and are weak fliers, ceiling and window fans can be used at high speeds to keep midges out of small areas.


A complete fly control program
is essential in any stable yard.