WASHINGTON - Scientists have identified the "come hither" scent that female German cockroaches use to lure males, a discovery that may help control one of the world's most troublesome and resistant household pests. Female cockroaches emit a pheromone, or chemical attractant, to let males know they are ready to mate. Researchers earlier identified the courtship chemicals used by other cockroach species, but the romance scent of the German cockroach remained elusive. "The German cockroach is the one we wanted because it is a worldwide pest that gives all the other cockroaches a bad name," said Wendell L. Roelofs, a Cornell...