As promised, here is some fly info:
House flies: You’re all familiar with these. They reproduce in moist material (like manure). They are annoying, but don’t bite and are probably the most common fly around barns thoughout the summer. You’ll find them anywhere on a horse, but often going for the moisture around the eyes. A housefly can live about a month.
Stable flies: These look somewhat similar to house flies but are slightly larger but have a real bite as they feed on the blood of warm-blooded mammals. They can bite though clothing; often on the ankles. After feeding, they will fly up and land on something to digest the blood. They prefer rotting vegetation like wet piles of hay, spoiled feed, or compost piles to lay their eggs. They can also travel far distances on wind currents.
Deer flies: These are larger flies that also bite and feed on blood. Deer flies are the ones with brown or dark patterns on their wings. They are often found in shallow water or moist ground along the edges of ponds or other natural water. They can fly a long ways from their breeding ground. We often encounter these on rides near woodlands. They attack and bite quickly.
Horse flies: These are the big black flies up to 3/4″ long that are also annoying biters to horses and riders. They fly around you before landing and don’t bite immediately so can often be “slapped” before biting. But their bite is painful. Like deer flies, they also are semi-aquatic breeders.
Horn flies: These flies come from pastured cattle and spend most of their lives on the animals, but will sometimes attack horses. You generally see them congregated in groups on the backs of cattle. They lay their eggs in fresh cow patties.
Face flies: These look similar to house flies but may be found on horses if cattle are nearby. They also lay their eggs in fresh cow manure. You see these flies trying to feed on secretions of the eyes, nostrils and mouths of cattle.
Black flies: These are the little gnat-like flies that come out in the early spring and circle in groups, usually attacking the tallest objects. These flies only reproduce close to clean, fast moving creeks or rivers but they can fly miles from the breeding ground. They are sometimes called May flies, but we usually see them from sometime in April into June. A breeze seems to limit their appearance. We haven’t had many out yet this year because of the cool weather and wind.
Dung flies: These are yellow and seen in or around compost piles and animal manure as the larvae feed on dung. The adults are beneficial as they don’t bite and feed on other files that reproduce in the dung. We like these flies!
Cluster flies: These look like larger house flies and are the flies that you see in lawns or fields but more often along window in the fall. They don’t bite mammals.
Bot flies: These flies look a little like honey bees and lay their eggs on the forelegs of horses. They annoy horses when they lay the eggs. The hatchlings penetrate the soft tissue of the horse’s mouth and are then carried into the animal’s digestive system where they can cause various problems until they detach and pass through the feces where the process starts again.
Methods of prevention and control of flies:
Manure management: This is one of the best ways we can control them as it can reduce both house and stable fly populations. The fly development cycle goes from eggs to larva (maggots) to pupa (like a cocoon) to an adult and can take anywhere between 10-21 days depending on the species and the weather (development slows down in cooler weather). So I try to scrape the paddock and clean out the run-in sheds or stalls once a week. The manure and hay from these tasks go on the compost pile which I also try to turn once every couple weeks. The compost pile itself generate heat which kill the developing flies.
Traps: There are several types of traps available. The one I have the best luck with is the sticky string that hangs around the perimeter just inside the indoor riding ring. House and stable flies go up to land on it and get stuck. The large trap with the black ball is for the big horse flies that think it is a horse or cow belly, fly down towards it, and then fly up when they realize it isn’t an animal, and get caught in the funnel at the top because they keep climbing up toward the light.
Shade, shelter, etc: The run-in sheds helps with fly protection because most flies avoid dark areas. If there is a breeze you’ll often see the horses standing on the earth mound in their lot because it is windier there and that helps with some flies, especially the little black flies.
Birds: The chickens and guinea fowl are helpful in eating the fly pupae. I imagine the peafowl would as well if they ever go outside and would use their beaks for eating rather than screaming.
Of course our friends the barn swallows can each eat an estimated 850 flies and other insects a day!
Predatory insects: We spread the mail-ordered fly predators for another “natural” preventative. I wish we had more dung beetles which distribute the manure but I’ve only seen a few.
Sprays: There are also natural sprays as well as chemicals such that can be applied directly to the horses. I don’t like using chemicals but we do use them some as I feel flies can be a safety issue, especially when riders are vaulting.
Material barriers: There are fly masks and blankets that can be used to keep flies from bothering horses. I tend to stay away from them unless a horse is particularly sensitive as I feel our other practices and the fact that flies, like cold, are part of the environment that horses are adapted to withstand. They have their hide, and you’ll often see a group of horses standing together gently fanning flies off each other with their tails.
We still have some flies:
Some still manage to find a way to survive and reproduce and since most flies do fly, we can’t prevent them from visiting the farm from the surrounding countryside. Unlike other visitors, we try not to welcome them!
First photo: Jake’s hide, bushy mane and tail, and hairy ears all provide some fly protection.
Second photo: The compost pile can be managed to minimize flies reproduction while turning manure into soil enrichment material.
Third photo: Two chickens and a guinea meet to strategize their fly control plan.
