Laboratory evaluation of scilliroside used as a rodenticide against the lesser bandicoot rat, Bandicota bengalensis

Abstract

SUMMARYThe toxicity and efficacy of the acute rodenticide scilliroside was evaluated in the laboratory against the lesser bandicoot rat, Bandicota bengalensis. The acute oral LD50 and LD 95 doses for males were 0·8 mg/kg and 2·5 mg/kg respectively, and for females were 0·5 mg/kg and 1·6 mg/kg, respectively. When caged bandicoots were given a choice between plain and poison baits, the optimum concentration of scilliroside was found to be 0·05%. Symptoms of poisoning appear from 22 to 34 min after feeding starts and the latency pattern indicated an abrupt ceasing to feed at these points. Death occurred from 2 h to as long as 6 days after poisoning, following prolonged convulsive seizures. There appears to be aversion to scilliroside at all concentrations in food baits. Maximum mortality attained on free-choice feeding on scilliroside was 90%. Despite these disadvantages, the material may have merit as an alternative rodenticide to zinc phosphide where acute toxicants are to be used.