Late summer and early fall is the time of year when the bot flies come out and yes they do drive your horse crazy. If you see your horse running for no reason more than likely a bot fly is after them. Bot flies look like a honeybee and are about the same size. They are very irritating to your horse.
There are three species of bot flies. They are the horse bot, throat bot and the nose bot. The horse bot lays their eggs on the legs, flanks, and sides, the throat bot lays eggs on the neck, mane and under the neck these two are the most common. The nose bot fly lays their eggs which are black on the muzzle, but they are rare in the United states. Bot flies are normally found around horses, but can also be found on dogs.
The eggs are yellow and on most horses they are easy to spot. The female bot fly’s only purpose is to lay eggs and she can lay between 300 to 1,000 eggs. If you see them around your horse don't be afraid to catch them and kill them. They have no stinger and no moving mouth parts to bite you with.
It is best to remove the eggs from your horse. The eggs cause the horse to feel itchy so they lick or scratch the area on themselves or another horse and ingest the eggs. Because of the moisture in the mouth and the warmer temperature it causes the eggs to hatch. The larvae then move from the mouth to the horses stomach lining where they stay until next spring. The larvae will pass through your horses feces and pupate.
The larvae will rob your horse of nutrients and cause digestive problems. They can stay attached to the stomach for 8 to 10 months which will cause the stomach to become inflamed and can cause ulcers.
To get rid of the eggs from your horse's hair try one of the following. Wash your hands thoroughly after you finish the process as you don't want the bot eggs to invade your mouth.
*Apply baby oil to the eggs to suffocate them.
*Purchase a bot block, which is grayish black in color and looks like a porous stone. When you rub the stone over the hair it removes the eggs.
*Bot knives have a serrated edge that is specifically designed to remove the eggs.
*You can also scrape them off using your fingernail, but this may take a long time.
When you scrape the eggs off make sure you take your horse to an area where they will not be grazing as you do not want them to pick them up again. Worm your horse after the first killing frost in your area and then again in the spring to get any late bot larvae. If you suspect your horse to have a heavy infestation of bot eggs consult your veterinarian before worming them.