There is no known method for eliminating the “Impressive Fire Ants” once they are established. Fire ants are spreading in the Lower Mainland as call goes up for legislation to prevent movement of soil that is infested. Attempts to eradicate impressive fire ants with pesticides have failed, they come back stronger than ever from pesticides. Though tiny, fire ants swarm quickly when disturbed and deliver a painful sting. They prefer warm, moist locations and spread densely around patio stones and yard structures, with up to four nests per square metre. Where the Impressive Fire Ant has been established, the movement of soil out of the area is going to greatly increase the chance of spreading this ant. Potted landscaping plants, soil for lawns and gardens as well as soil excavated from building sites are likely how the insects are spreading in B.C. Digging up nests during the winter months when the ants are inactive allows the entire colony to be removed and then killed in a deep freeze. When they are dormant, the ants all cluster up into a fist shape, so we were able to locate nests and dig them up. During the summer, the Impressive Fire Ants burrow and scramble away with egg masses very quickly when disturbed. The best defence against fire ants is to ensure your yard does not become infested in the first place.
Widespread infestations could also render parks unusable to locals and tourists. The ants are entrenched in a variety of residential neighbourhoods, from North Vancouver Deep Cove Park, Richmond’s McDonald Beach Park, South Burnaby, Victoria, Oak Bay, Courtenay, North Delta, Maple Ridge and Chilliwack.
http://www.delta-optimist.com/opinion/blogs/deltabc-1.983313/blog-south-delta-is-not-immune-to-the-impressive-fire-ant-1.1992429