Abstract: A plumbing trap in the form of a fitting for installation in a vertically disposed waste pipe, characterized by axially spaced and aligned upper and lower tube sections with an annular opening therebetween, said opening being in communication with a chamber surrounding the upper tube section, and in which there is killing means alternately in the form of a pool of poison or an electrically charged conductor, said opening and chamber providing space in excess of the jumping and bridging capability of the roaches, whereby they are forced to pass over the killing means.