Methoprene for control of horn flies: application to drinking water of cattle via a tablet formulation.

A tablet formulation of methoprene, an insect growth regulator, was effective for control of Haematobia irritans (L.) in the manure when used in the drinking water of cattle. In large field troughs, a simple dispenser provided the turbulence necessary for erosion of the tablets. A minimum of 0.02–0.03 ppm of methoprene in the water was required for consistent control.