March 2019 - Fly Control Options
Written by CRM
Wednesday, 27 February 2019 05:22
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Getting a head start on pest control is even more important after an extra rainy season.

This effects of this winter’s heavy rains have not stopped at road closures, mud slides and seriously altering training and show schedules. They’ve also made a wetter environment that fly and other pest larvae love and will thrive in. So, along with our currently emerald green grasses and hillsides, a heavier than usual barrage of flies is expected this spring and summer.


Fortunately, there are plenty of ways to mitigate flies. Environmental management, sprays and topical repellents, feed-through and predator products and physical barriers like masks and fly sheets are available in myriad options, fitting many budgets.


Combining several strategies is critical, notes SmartPak spokes veterinarian Dr. Lydia Gray. “You’ve got to group everything together,” she stresses in a video Q&A on the subject. Thinking of any one approach as an alternative to another typically won’t produce great results. It’s a challenge that needs to be tackled on every front possible, and starting now by implementing strategies and getting defenses in place.

Get A Head Start

Manure is fly heaven and should be kept as far from horses as possible. Remove poop and wet spots in the stall as often as possible, keep the manure pile in the furthest corner of the property and haul it away as frequently as possible.

Any form of organic matter is also fly heaven. Food waste in unsealed containers and rotting vegetation are more fly magnets that can be easily eliminated from the stable environment.

Place fly traps strategically. Some traps use a sticky substance to catch flies where they are, and other uses an attractant to lure flies. Place the latter where it will lure flies away from your horse, not toward it.

Fans are good for blowing flies off horses, too.


Fly sprays work in three main ways. Those with an insecticide, either natural or synthetic, attempt to kill flies or at least knock them down. Those with a repellent make the horse unattractive to the fly; and a third type “confuses” them, explains Dr. Gray.  “They don’t get the signal from the horse that it’s a tasty morsel, so they don’t land on them.”

The big range of products in this category varies from those you’d apply several times a day to every few days or every two weeks. Absorbine’s UltraShield EX Insecticide & Repellent is a recent addition to this category and is billed to address the “most challenging” horsekeeping conditions. It kills and repels more than 70 species of biting and nuisance flies, along with mosquitos, ticks and gnats, the company reports. It’s weatherproof for up to 17 days, Absorbine says, and can also be used as an effective premise spray along with its application directly on the horse.

Along with premise sprays, overhead fly spray systems are a popular option for misting natural insecticides through the stable on a set schedule through the day. Testing the type of spray delivered is important as allergic reactions are a risk, as they are with sprays delivered through any means. Test the product on a small patch of the horse’s body for a few days and monitor that there are no adverse reactions.


Fly sheets are getting lighter, more breathable and more durable by the minute, so they can be good options for horses even in hot climates. A new barrier product from SmartPak is Kool Kurtains, a “technically-advanced product that is scientifically proven to deflect up to 80% of the sun’s heat rays providing passive cooling to barns, run-in-sheds, stalls, kennels, aisleways, hay storage buildings and other agricultural facilities,” states SmartPak. They are also designed to “screen out bugs and birds, yet allow for airflow and provide easy access for horses, people and equipment.”


These stable-safe “beneficial” breeds of wasps are released near fly breeding grounds. They invade the fly larvae, lay their own eggs there, killing the fly eggs in the process while adding more “beneficials” to the environment. Predators are released regularly, usually monthly, to counter the fact that flies reproduce freakishly fast.

Spalding Labs hatched its first batch of Fly Predators over 40 years ago and is going strong. Arbico Organics is another longtime maker of gnat-sized parasitic wasps: their brand is Fly Eliminators.

Feed-Throughs (aka Insect Growth Regulators)

These are fed to the horse, pass through its digestive system and come out in manure, where they destroy the “chitin,” a part of the larvae skin necessary for its survival. Because horses don’t have chitin in their system, IGRs are considered safe for horses. They need to be fed well before fly season starts in earnest and fed regularly as directed.

Along with topicals, Farnam offers two products in this category: SimpliFly and EquiTrol II. Both are highly palatable and effective in breaking the fly life cycle and preventing larvae from becoming adult flies. SimpliFly has the added benefit of being the “only feed-thru fly control granted reduced risk pesticide status by the Environmental Protection Agency.”

Price, horsekeeping preferences and, most importantly, what works best in your stable, and with its type of flies, will help determine which combinations of methods and products are the most effective.

The importance of fly control goes beyond simply reducing their annoying presence. They can carry and transmit diseases, many breeds bite and all flies and pests detract from what should be a calm, pleasant environment for horses and humans to enjoy their time together. They can also be an issue in areas where horses live next to not-so-horsey neighbors, generating complaints that complicate an already tough challenge in residential neighborhoods.