This invention is the modification of widely available plastic household plumbing caps to serve as poison bait stations for killing colonies of little fire ants which have infested southern states and Hawaii creating misery for residents due to their bites. The modification consists of inserting into the caps metal screens with wire spacing adequate to allow passage of the tiny ants into the caps but preventing the bait granules from falling out. The bait stations so formed restrict the poison bait access to little fire ant or smaller insects and are protective of the environment and animals.