Here’s a really sneaky way to get rid of fire ants. (All’s fair in love and the war against insect pests.)
The only way to get rid of an infestation is to assassinate the queen. Wait until a dry spell is about to end. Sprinkle instant grits on the fire ant hill. The workers will carry the grits to the queen for her royal meal. She’ll eat the grits and when it rains, she’ll drink. And that’s what will kill her. The grits will expand in her stomach and she’ll “bloat” to death. Once she’s out of the way, the leaderless ants will die off. (This suggestion came courtesy of the Tightwad Gazette II book.)