Methods of testing rodenticides in the field against rats

Abstract

Poisons used in bait to control rats are of two kinds; single‐dose acute poisons and those with a slow or cumulative action lethal only if two or more daily doses are consumed. The two types require different baiting techniques and different methods must be used for testing them in the field. For acute poisons, the relative sizes of rat infestations have to be measured by baiting with unpoisoned bait both before and after poison baiting and the pre‐treatment sizes taken into account when analysing the results. When testing possible cumulative or multiple‐dose poisons, pre‐treatment baiting is unnecessary and the method used was that originally devised for field testing for anticoagulant resistance in rats. Examples of published results of field trials of both types of poison are discussed.