I am having some success with using beneficial nematodes. I’ve been spraying the area where they are going into the ground and putting as much down the tunnels as possible. I try to apply after rains as the ant feeder sites are often on non irrigated areas. The nematodes live longer and multiply faster in moist soil.
I think the main nesting site is on someone else’s property as I have not found it yet.
I am also spraying the foliage of the plants they are harvesting with Biorganic spray. It is a mix of essential oils. They change their feeding site after an application of this.
I have not had much success with boric acid or DE in treating them. They often forage up to 2500 feet or more from the main colony and can nest 10 to 12 feet underground. We have very sandy soil so they can go quite deep and they have many underground tunnels to the main nest site. I have tried many, many things over the last 25 years.
They are fascinating creatures, but what a pain! Good luck!
