There seem to be a lot of different things that kill ants. Inside the house a year or so ago I noticed a lot of ants eating on the dry cat food, so dropped a few white mints around it and all the ants left, haven't seen them since. Tried it on the outdoor ants and they swarmed over the mints, probably a different breed. So had to go to the old faithful sugar and Boric Acid mix for them. Some ants are so strong they use that for flavoring, so had to use some DH got years ago at the drugstore that must have arsenic in it, it kills everything.
Now I'm putting Diatomaceous Earth around again, it usually clears out most critters that chew on my plants. I mix it with water and spray it on everything, it drys and leaves a white powdery look, but the critters leave or die. Not many ants after that for quite a while.