Campground Hosts & Ants?

I'm a fan of diatomaceous earth for controlling ants and other insects for one major reason: it is completely non-toxic to mammals. The stuff does, however, have to be kept dry, even a good case of morning dew will inactivate it. But it is cheap, can be sprinkled around under the furnace, sink, and other out of the way places, and as long as it stays dry as those places should be, any insect that goes there dies. You can get the recommended stuff, food grade (yes, you can and no doubt do eat it all the time) here:diatomaceous earth (food grade)

You can read all about it here: about diatomaceous earth