Posted: 30/06/2013 at 22:09
Hi Sheila, I agree with Verdun that the best solution is nematodes which are a natural method. The nematodes in question are called Steinernema feltiae which occasionally naturally infect and kill ant nests. Most of the alternative solutions involve poisons which are taken up by the ants (and hence whatever happens to eat the ants, such as some birds) and the small amount of poison may build-up in these larger animals over time and cause unexpected and more serious problems, perhaps similar to what we may be seeing in bees.
The best known ant nematode producer is Nemasys which sells a product called "Nemasys No Ants". You just water them onto an already damp lawn.