Laboratory evaluation of the anticoagulants coumatetralyl and brodifacoum againstRattus argentiventerin Peninsular Malaysia1

In laboratory toxicity tests using individually‐caged rice field rats, Rattus argentiventer (Robinson & Klossl, complete mortality occurred when the rats were fed on broken rice/corn oil bait containing 0.0375% coumatetralyl for four days. Equivalent kills were obtained when rats we're fed 0.002% and 0.005% brodifacoum for one day. Both compounds were more toxic than warfarin at 0.025%. Choice tests showed that 0.001% and 0.0005% brodifacoum were as acceptable as 0.025% warfarin, but higher concentrations and 0.005% and 0.0375% coumatetralyl were poorly accepted. The potential advantages of coumatetralyl and brodifacoum over other rodenticides for the control of R. argentiventer in rice fields in Malaysia are discussed.