Fly control strategies for horse owners

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Flies are among the most difficult horse pests to control. Some species of flies are blood feeders. Non-­biting flies can also cause problems as they can carry diseases and can be very annoying to both horses and humans. As rural areas are increasingly encroached upon by urban sprawl, nuisance lawsuits are on the rise too. With this in mind, it is no wonder that fly control is of vital importance to today’s savvy horse owners.

Some common flies of concern to horse owners are stable flies (Figure 1) and house flies (Figure 2). House flies and stable flies are problems in and around barns and stables.

Stable Flies Stable

Stable flies are dark colored, 3/4-inch long, and have piercing bayonet-like mouthparts that extend from under their head and have "checkerboard" markings on the underside of the abdomen. Their life cycle is about three weeks in summer and longer in cooler weather. Females deposit 400 or more eggs during their life. Stable flies feed on most species of domestic livestock, but are major pests of horses and cattle. They penetrate the animal's skin with their piercing mouthpart and feed on blood. They primarily feed on the front legs, causing animals to bunch in a circle with each animal trying to protect its front legs.

House Flies

House flies are similar in appearance to stable flies and develop in similar material. Because house flies have sponging mouthparts, they cannot pierce the skin of an animal. Instead, they feed on animal wastes, decomposing feeds, and other liquefied organic matter. The life cycle of the house fly is about two weeks. House flies have been incriminated in the transmission of many animal and human diseases.

What can horse owners do to control flies?

There are several steps that will aid in the control of flies in and around barns. In order for flies to reproduce they require appropriate breeding material, optimum moisture and adequate warmth. By eliminating any of these, you will reduce the fly's ability to produce a new generation. Therefore, a successful fly control program must include the following methods:

  1. Sanitation
  2. Mechanical control
  3. Proper use of insecticides

Sanitation should be first and foremost. Manure and other fly breeding material are best disposed of by spreading evenly over pastures. Composting the manure and bedding is also effective. The heat generated by a properly maintained compost pile will kill fly eggs. Additionally, be sure to clean up spilled feed and other organic materials to prevent additional fly breeding grounds. Reducing moisture in stable areas can also reduce fly development. Corral areas should be designed to promote adequate drainage and eliminate wet areas too. Automatic waters in or around the barn should be properly maintained to avoid wet spots. Stalls should be regularly mucked out and dry bedding should be readily available.

One of the most common means of mechanical control is the use of screens. Screens do a good job of keeping flies out of barns. The disadvantage is the maintenance and additional cost of installation. Most people are also familiar with the electric bug zappers and jug traps. These can eliminate many flies, but will not usually give satisfactory control when active fly breeding takes place.

Finally, the use of an insecticide plays an important role in any fly control program. Even with good sanitation and moisture control practices in place, flies can still become a problem. Insecticides are usually needed as the final piece of a complete fly control plan. However, insecticides alone cannot replace good sanitation and moisture control practices. One insecticide product to consider in your fly control program is the STOCKADE® Rabon® fly control block. This self-fed block contains Rabon which prevents the development of house flies and stable flies in the manure of treated horses. In addition, this block provides needed vitamins, minerals, protein and salt in one convenient block. Just place the weather-resistant STOCKADE Rabon Fly Control Block out in the pasture or paddock where horses will have regular access.

What is Rabon?

Rabon is a nontoxic oral larvicide (meaning it kills fly larvae). Rabon controls fly populations by preventing larvae from developing into adults. Rabon passes safely through the digestive system and remains in the manure to kill developing larvae through physical contact. Rabon remains active in the manure for roughly 3 to 4 weeks under normal circumstances. Because Rabon® inertly passes through the digestive system, Rabon is completely safe and can even be fed to pregnant or lactating mares. Rabon is also environmentally safe and treated manure can be safely used as fertilizer.

Using STOCKADE Rabon fly control blocks effectively

It is vital that all horses on the premises are treated with proper amounts of Rabon for effective fly control. Read and follow label instructions carefully and monitor consumption. Remember that just one female can result in over 300 MILLION flies in 60 days! Neglecting to treat or under supplementing even one animal can sabotage your fly control efforts. For maximum benefit, offer STOCKADE Rabon fly control blocks 3-4 weeks prior to fly season and continue until the first killing frost. When introducing Rabon later in the fly season, remember that Rabon will not kill existing adult flies. Other insecticide products will need to be used to control these adult flies.

In summary, you shouldn’t wait until a problem exists to begin a fly control program. A good program needs to be set in place before fly numbers increase. The more flies present when control measures are started, the longer it will take to lower the population to a satisfactory level. If you choose to use insecticides, make sure you read and understand the directions. Unfortunately, there is no “silver bullet” in the war on flies; however, use of STOCKADE Rabon fly control blocks provide a sound foundation for your fly control program in addition to sanitation and mechanical controls.

For more information on the use of STOCKADE Rabon fly control blocks, call 800-835-0306.