Laboratory Evaluation of some Additive Poison Baits for Controlling Commensal and Field Rodents

Laboratory studies were conducted to explore the potential of various additives for enhancing bait acceptance against commensal rat (Rattus norvegicus) and field rodents (Bandicota bengalensis and Nesokia indica). Whole egg, milk, yeast, fish meal and minced meat (beef) were incorporated at 3% (w/w) and 5% (w/w) individually. Under no-choice test, the rat species showed a variable level of liking for minced meat, yeast, fish meal and egg baits over plain bait. Under paired choice test, R. norvegicus preferred egg bait 64.96% and 62.97% in 3% and 5% combinations over plain bait. Similar pattern of preference for egg bait was recorded in B. bengalensis i.e. 58.61% and 54.23% and N. indica 46.20% and 57.20% in 3% and 5% combinations respectively. Under multiple choice tests, egg was emerged as the top-preferred candidate. In case of R. norvegicus, egg bait (3%) containing brodifacoum and bromadiolone (0.005% each) significantly enhanced the bait intake (68.21% and 60.09% respectively) compared with non- additive poison bait. Under B. bengalensis and N. indica, egg mixed brodifacoum (0.005%) significantly increased bait acceptance in rats (79.81 % and 60.59%) over poison bait without additive. A prominent preferential trend was also noted in egg additive bromadiolone baits (58.92% and 50.30%) in both the field rats. It is therefore, concluded that egg additive in poison bait can be helpful in enhancing poison bait acceptance by commensal and field rodents.