I agree with Martin #74 and here is why. I use to hire a bug company and they sprayed everywhere esp. outside to combat the ants. Problem became worse. I realized when they sprayed outside. Hmmm. this killed all the food for ants. so they came inside and moved under my house I believe. 2 things have helped me. I feed them cat food around the perimeter of my backyard they love it and also let these daddy long leg spiders reside in all the corners of my house. they are benign and when you look at the pile of ant bodies below their webs you will be amazed. so they kill the few scouts who meander in and I feed the large flock outside. The ants have actually built a pyramid with my face on it outside (just kidding) but I have had the best antless summer. (occasional attacks occur that are shortlived.) Hearts and minds so to speak.