I used to buy some stuff for outside ant hills. I don't remember what it was called though. It smelled incredibly bad and I had to get it at the real garden center. It's for mixing up and spraying bag worms. It really worked. I would just sprinkle a little around each ant hill and they would be gone by the next day. I had a really bad ant problem because it was a new house and because of digging the foundation it disturbed all the ants.