Breaking the Bot Fly Cycle with Janice Spears

The horse will either scratch, bite or lick at these areas where the bot have laid their eggs and the eggs will hatch in the horse’s mouth. The bot larvae eventually make their way into the stomach lining and/or move further into the intestines, causing damage to the linings of these organs. To slow down this cycle it is best to worm after the killing frost as there will not be as many bot flies laying eggs to start the cycle over.

Paste wormers that are labeled for bots are:

• Equimax
• Quest
• QuestPlus
• Zimectrin
• Zimectrin Gold

Be sure to give the correct amount of wormer per body weight of your horse. A weight tape will not be exactly correct, but it is better than trying to “eyeball” the weight of your horse.

ALWAYS follow the directions found on the box or tube of wormer. If your horse has no history of being wormed, it is recommended to use a ½ dose of Fenbendazole first so that not all the worms are killed at once and might cause colic from a worm overload. Then wait a couple of weeks and come back with one of the paste wormers to get the bots!