Not one weapon, not even two. When it comes to battling flies, bring out the arsenal -- Those flies which have colonized your horse's face didn't even exist in this country prior to the mid-1950s. But after they hitched a ride from Europe to Canada, getting fruitful and multiplying didn't take long.
Annoying, for sure, but face flies are considerably down the list when it comes to worst enemies. The biters--stable flies, deer flies and horse flies--have clearly earned that distinction.
The first line of defense is to prevent flies from breeding. Proper manure management and moisture control are the two biggest factors. Remove manure and wasted feed daily from stalls and pens and either spread it thinly to dry or compost it. If manure is spread daily, it must be distributed thinly and harrowed to encourage rapid drying, eliminating favorable conditions for fly larvae. It is best to spread manure away from areas currently housing horses.
For those flies that manage to breed, preventing the larvae from hatching is the second line of defense. Based on the fact that flies lay their eggs in manure, feed-through products "sterilize" the fly's food source at the beginning of the insect's life cycle. Any larva that hatch in the manure produced by a horse on a feed-through product will die before it has the chance to develop.
Virginia horseman Jim Drunagel tried one of these products last summer, choosing a block rather than a feed supplement.
"We rented a nearby seven-acre field to turn a few horses out," he recalls. "I don't know why the flies were so bad, but when you'd go over there, there would be a thousand on each horse. You'd think that they just couldn't make it like that.
"So I bought some Rabon blocks. I'm going to say they helped 50 percent. Without that and the fly masks, those horses couldn't have made it over there," he says.
These products are safe for horses, manufacturers claim, because they have low toxicity levels. In order for the product to be effective, however, all the horses in a given area must be ingesting the product. Otherwise, larvae will hatch in the untreated manure, and the fly population will continue to grow.
Feed-through products are effective only against house flies, the only fly pest that incubates in fresh manure. (Stable fly larvae develop in manure mixed with straw, soil or grain and in wet straw, hay and grass clippings. Round bales in contact with moist soil may also serve as a larval development site.)
Tiny wasps that parasitize flies are gaining in popularity as a control method that is safe for the horse and gentle on the environment. These wasps feed on the larvae of the fly while it is still in the manure. They do not bite or sting humans or other animals and are so tiny that they go largely unnoticed.
During fly season, these parasitoids must be replenished about once a month; even though they are reproducing, they are unable to multiply in sufficient numbers to control the vast number of flies usually present in areas where horses are kept.
If some flies succeed in hatching, capture them immediately. Jar traps that utilize attractants can capture thousands of flies. Some systems use a pheromone (sex attractant) to draw the flies, others require baiting with fish or meat. Disposable traps are also available.
Fly paper is available in several widths, some designed to hang from the ceiling, others to be tacked across doorways or aisles. Some contain pheromones, others are merely sticky. A few brands contain insecticides, so read the label if you plan to use them around food or animals.
The fourth line of defense is to kill the remaining flies. Killing generally means insecticides. While insecticides are an important part of many fly control programs, much less must be done with them if manure and moisture are managed properly.
What type and brand of insecticide works best depends on weather, management and a horse's individual sensitivities. Finding the best one involves a certain amount of testing for effectiveness and allergic reactions (both human and horse).
Topical sprays can be purchased in ready-to-apply forms or concentrates that are usually diluted in a 1:7 ratio of insecticide to water for house flies or a stronger mix for other flies. Insecticides can also be used in foggers and misters. Certain general livestock sprays are not safe for use on horses.
Strips impregnated with insecticide are designed to keep approximately 1,000 square feet free of flies for about four months, and could be useful for enclosed areas such as tack rooms, feed rooms and offices. Read the label--some are not safe in enclosed areas that humans frequent or in areas where food is present.
Baits don't work with stable flies, though they are useful in controlling house flies and blow flies. The idea is to attract and entice flies to eat a specially prepared food that is laced with insecticides. Stable flies feed on blood and are not attracted to them. Be aware of the potential danger to other animals and children.
Applications of residual insecticides to sites where adult flies congregate are also beneficial in controlling both house and stable flies. That includes the outside of stalls and fences, for example, and the nearby landscape. During the hot parts of the day, both house flies and stable flies rest in nearby trees and other vegetation. Keeping weeds mowed reduces the amount of shade available and restricts favorable fly habitat.
Stable sprays are usually sold as concentrates that are diluted and applied with sprayers. Some premise sprays are not safe to use on horses, manure or bedding.
Residual sprays remain active for several days. Rain washes the residual sprays off treated surfaces, so they should be re-applied following a rain.
Finally, you need to protect your horse. Repellents are available as sprays, lotions, wipe-ons, gels, dusting powders, ointments, roll-ons, shampoos and towelettes.
Repellents contain a substance irritating to flies, such as oil of citronella, and most contain some insecticide (mostly pyrethrins and permethrins) as well. Repellents can be water-, oil- or alcohol-based. Oil-based repellents remain on the hair shaft longer, but the oil attracts dirt.
Repellents can also contain sunscreen, coat conditioners and other products that increase lasting power. How long a repellent lasts depends on the weather, management, exercise level of the horse (how much he sweats) and grooming.
"We use a fly spray that is an all-natural-type of material," Drunagel says. "It is made with citronella and smells pretty decent. We've probably had more luck with that one than any of the rest.
"There again, if you're teaching a class, you have to take a bottle of spray out with you and re-spray some of the ponies that are prone to flies after about 30 minutes.
"The roll-ons are good, too, and the creams. They seem to stay on longer without evaporating."
Some fly masks protect the eyes while others protect the eyes, ears and jowls. Most are made of a mesh that allows the horse to see.
Attachable (halters and bridles) strips impregnated with repellent are useful for controlling face flies and can last several months. Some degree of relief can also be afforded a horse by using fly shakers (with or without repellent) attached to the crown piece of a halter or brow band of a bridle. These strips mechanically jiggle the flies off a horse's face when he shakes his head.
Bill Walsh is executive editor of The Mane Points.
Equine insecticides generally fall into one of four categories: pyrethrins (natural insecticides made from chrysanthemums), permethrins (synthetic pyrethrins), carbamates, and organophosphates. This list goes from least toxic to most toxic and from least long-lasting to most long-lasting. Insecticides are available in many forms for various applications.