Name: Haematobia irritans

Alias: Horn flies are the reason that cow tails exist. They are the small flies that crawl all over cattle during the hotter months of the year. Although they look similar to houseflies, they have completely different life cycles, reproduction habits and feeding preferences. Females lay their eggs in cattle manure, where it lives during its larval stage.

Crimes: Horn flies feed on livestock by using their piercing/sucking mouthparts to draw blood out of animals. This causes significant stress on the animal, and can reduce weight, body conditioning and quality of life. They can cause infections and transmit diseases.

Redeeming qualities: The larval stage helps break down cow manure faster to return manure nutrients back into the soil. This helps the ecosystem continue.

Sentence: There is a wide range of solutions for controlling horn flies, the most common being chemical treatments. Ivermectin and permethrin-based pour on products are the most common. Ear tags can also be used that are enlaced with diazinon that keeps them at bay all season long. Chemical dusts can be applied by simply placing a backrubber in a location where the cattle have access to it, and the cow can apply the chemical themselves as they use or walk under the backrubber. One potential problem is that horn flies are developing resistance to insecticides, and there are no new products used to kill them. Be sure to switch the chemical mode of action you are using regularly and be sure to always read and follow label instructions.

For more information on dangerous and beneficial bugs, call UI Extension educator Joseph Sagers at 208-270-4031 or email