posted 9 years ago
Fire ants aren't frost proof, they are a tropical ant that goes underground at night to avoid freezing temperatures. So during the cold season I'll go out late on sunny winter afternoons when there is a hard frost expected that night and scatter the mound and ants downwind as far as I can toss them. Any ants that can't make it back underground before nightfall are dead. It usually takes 2 or 3 visits to completely depopulate the mound.
During the frost-free season I'll go around with a wheelbarrow filled with soapy water, shoveling each mound into the soapy water where the surfactant quickly kills the ants. After 2 hours I'll dump out the dead ants and soil. Once you've dug out the first couple of shovelfuls and the mound is disturbed, allow 5 to 10 seconds for a thick layer of ants to form on the soil's surface before skimming off the ants with a thin layer of soil, then repeat the process. After a number of cycles of this when the ants start getting thin on the ground, I'll stop, give the surviving ants a few days to regroup before making another visit.
I've been using this method for over 14 years to control fire ant mounds on my 26 acres of pastures. It's a continuing process since each summer alates start new colonies and mature colonies will relocate across the property line from adjacent pastures, but it has been very effective at controlling fire ants on my property.