Abstract :
Rodenticide baiting and trapping are the common methods for the control of the house rat, Rattus rattus, which is a predominant commensal and agricultural pest throughout the tropic and sub-tropic regions of the world. During the present studies, a synthetic form of carbon disulphide (CS2), which is considered to be an artificial semiochemical involved in mediating socially induced food choices, at its 0.5%, 1% and 2% concentrations in cereal bait (mixture of broken wheat grains, sugar powder and groundnut oil 96 : 2 : 2), attracted both male and female R. rattus in bio-choice feeding tests with individual rats and pen experiments with groups of 10 rats and also in field experiments in poultry house premises. Addition of 1% CS2 in 2% zinc phosphide, 0.005% bromadiolone and 0.0025% difethialone baits significantly improved bait acceptance by R. rattus. (Corresponding values of per cent acceptance of scented bait over the unscented bait were 77.3, 74.2 and 65.9.) Similarly a greater number of rats were trapped with cereal bait containing 1% CS2 than without it in pen and field experiments. In poultry houses CS2-scented bait was effective in improving the trappability of rats during the first 3 days, after which it did not have a significant effect on the residual population.
