Did the Amdro thin them even momentarily? I haven't used it in over twenty years but they used to recommend at least two applications and the stuff worked. Maybe they HAVE developed an immunity. Try it once more, just like taking your antibiotics. Don't facilitate the natural selection of the SUPER ANT! You wouldn't want that on your conscience.
It's like they didn't even eat it. But they were carrying in down into this particular nest that has decided to invade my kitchen. I've used it in the past to varying success, I think that some species just ignore it altogether. When it dries up a bit from the
And these are the little black tiny bastards. I just put out some Terro. I got a bottle and some outdoor bait stations. For $12 what the heck? They were eating the hell out of the pad I laid right in their path from the wall to my coffee pot within about a minute, it has a solid black ring of ants around it right now chowing down. I really don't know what they are wanting in the coffee pot, there's no sugar in it or anything, maybe the water?.