In some regions, early fall brings a bumper crop of bot flies, and with them a rash of bot fly eggs that you’ll want to remove. Larvae that matured inside the horse and exited via manure in the spring are now hatching into flies. In the next step in their life cycle, these flies will lay eggs on strategic locations on a horse. When he licks the eggs they hatch, a new generation of larvae enters his mouth and the process is repeated.
You most likely deworm your horse against bots to kill the internal larvae, but you can further diminish their numbers by removing eggs before they have a chance to hatch.
Bot eggs are sticky and yellowish, shaped like small grains of rice. They are commonly deposited on the knees and forearms up to the chest. The eggs can be removed using on of two tools.
On option is a bot knife, which has a rounded blade with a serrated edge. Place the knife above the egg and scrape downward. The egg will fall to the ground, so be sure to do this far from where your horse grazes.
It’s best to consult your veterinarian in regards to the proper worming program for your horse.