Amdro is a trade name for a hydramethylnon-based hydrazone insecticide, widely used across the southern United States to control fire ant populations.
Patented by American Cyanamid in 1978 and conditionally approved by the United States Environmental Protection Agency in August 1980, Amdro operates as a delayed-toxicity bait. Soldier ants carry the corn grit and soybean oil–based granules into the mound, where it is fed to the queen. Her death typically collapses the colony. The formulation must be used within three months of opening to retain potency. The method is slow — control can take up to a month — and the bait loses all effectiveness when wet, limiting its reliability in regions with frequent rain. It cannot be applied to food crops, restricting its use to ornamental landscapes, lawns and non-agricultural sites. The brand is now owned by Ambrands.
