Continuing with our discussion on how best to control flies and biting insects that torment our horses, last month we covered wearable, physical barriers – fly masks and bonnets, leggings and fly sheets, and began to look at some of the many fly sprays, wipes and repellents on the market.

It can be overwhelming to try to choose the best product. Not every fly spray will work equally as well for every horse, and horse keepers often spend a lot of money through trial and error before coming up with one they like. Some might be longer-lasting than others, but contain chemicals that can be ingested – both by the horse and the person applying the product – which in the short term aren’t harmful to humans or horses but can be toxic to birds, fish and honeybees.

Today a number of fly repellents are made from natural essential oils, such as oil of peppermint, cedar oil or pyrethrum (however, there has been much confusion regarding pyrethrum, pyrethrin and permethrin).

Pyrethrum comes from a species of chrysanthemum and has been used for centuries as an insecticide in the Middle East. According to Laura Pickett Pottorff, Colorado State Cooperative Extension horticulturist and plant pathologist, pyrethrum is the most widely used botanical insecticide in the U.S. Pyrethrum is non-toxic to most mammals, making it a safer alternative.

You can make your own fly repellent by using the dried flowers ground into a powder or mixed with liquid into a spray. Its active ingredient is pyrethrin, which is extracted out of the pyrethrum and is more potent. Most insects are highly susceptible to pyrethrin; it is irritating to them and acts rapidly, causing flying insects to drop almost immediately after exposure. However, many insects will recover after their initial “knockdown.” In order to increase insect mortality, the concentrated pyrethrin is often mixed with a synthetically made chemical synergist, such as piperonyl butoxide (PBO), in order to create products such as permethrin.

Both pyrethrin and permethrin are classified as restricted use pesticides by the EPA. Because pyrethrin is derived from a natural source (mums), it is biodegradable when exposed to oxygen, moisture and sunlight. However, permethrin is toxic to fish and highly toxic to bees and other beneficial insects and can be fatal to cats when exposed to concentrated amounts. Caution must be taken when using these products.

In researching for more natural oils/less chemically based repellants, several products came up, such as Cedarcide, EquiShield and Wondercide.

We’ve used Cedarcide Topical Flea & Tick spray for dogs, cats and horses with good success. Its active ingredients include cedarwood oil and soybean oil.

This product can also be used for humans. It’s also made for indoor use – spray doorways, window frames, carpet, furniture, pet areas and other indoor spaces but not in food preparation areas.

EquiShield FG Fly Guard by Kinetic Vet is described as a natural repellent used to deter ticks, biting flies, mosquitoes and gnats. Active ingredients are citronella, cedarwood and peppermint oils.

We’ve used both products on our horses and found they work equally as well as the old standbys that were chemically formulated.

Yet another product recommended to us is Wondercide. It offers a variety of flea and tick sprays and products for pets, home (indoors) and yard. Active ingredients include cedarwood oil, sesame oil and sodium lauryl sulfate.

Horse Tales: More on fly away flies

In order to apply fly repellent to your horse’s face, spray a cloth with the repellent and carefully wipe around the ears, eyes and muzzle. Don’t forget under the jaws as well. Photo by Judy Van Put

This is an overview of some of the many products on the market that rely more on essential oils – natural products – rather than solely on chemicals that may be harmful to ingest and to the environment. It’s important to research and try out a product before making your choice.

Of course, in addition to using fly repellents and physical barriers, horse keepers need to be mindful of where their horses are stabled and turned out. Standing water is a magnet for mosquitoes and all sorts of annoying insects. Gutters with downspouts leading away from the barn or underground and proper drainage should be utilized around the barn and paddocks to prevent puddles or standing water, especially near commonly used areas such as waterers, hay stations and feeders. Old-fashioned fly paper or sticky fly sheets can be used inside barns, stalls and sheds.

You might also consider another the use of fly predators, commonly referred to as biological pest control. These are used to treat your farm/property, not your horse. Fly predators are tiny gnat-sized insects that are found throughout North America. They are nocturnal, burrowing, predatory fly parasites that do not bite or sting animals or humans. They will destroy flies in their immature stage.

Fly predators arrive in a small pouches containing a sawdust-like material mixed with three species of the tiny larvae. The number of predators is calculated by the number of horses and the size of the property where the horses are turned out. The directions call for sprinkling the product on fresh manure, rotting organic matter, spoiled hay, etc. These fly predators can travel 150 feet.

Although they do not totally eliminate the fly population, they will minimize it as long as you maintain a sufficient amount by adding supplemental shipments every three to four weeks throughout the fly season to keep the population balance that is necessary for fly control. We have used fly predators with good results in the past, and even felt that the next year our property seemed to have less flies as a result of past use.

By utilizing a combination of the products noted above, you can win the “war on flies” and make your horse safer and more comfortable from biting insects throughout summer.

by Judy Van Put