Roach bait

Roach bait describes the most effective methods used to kill roaches, ones that function on viral principles. Roach Motels are one example. Since roaches actually live in nests, it isn't enough to simply kill the one or two roaches that happen to wander into a trap, as plenty of others won't. Even if you kill all the adult roaches outside the nest, some live eggs will remain in the nest and eventually hatch, which will leave you with the same problem you had before.

So, in order to kill the nest, Roach Motels don't trap individual roaches. Instead they lure roaches in, let them eat a pleasant tasting morsel of concentrated slow acting poison, and let them out. Slow acting contact poison with a lure in the middle will also do the job. Soon that roach dies but that poison remains in (or on) its body, which the other roaches soon eat, and become poisoned as well. In this way, each roach not only becomes a dead roach crawling, but also acts like a Typhoid Mary to the other roaches. Eventually the nest fills up with poisonous carcasses, turning the nest itself into a death trap.