Effects of ecological factors on the performance of rodenticides in sugar cane

Abstract

The sugar cane fields located near river Sutlej at Ladhowal (Lat. 30° 56’N, Long. 75° 52’E) were found infested with 4 rodent species namely,Bandicota bengalensis, Rattus meltada, Tatera indica andMus spp. Of these,B. bengalensis was most predominant. Compared to the adjoining wheat, paddy and mung crops the sugar cane fields at growth and maturity stages harboured high rodent population due to frequent waves of rodent immigration as a result of heavy rainfall and flooding of paddy fields in August and September and agronomic operations related to paddy-wheat rotation in most of the fields. Multiple poison baiting of rodents with brodifacoum (0·005%) and zinc phosphide (2·4%) in different fields of sugar cane resulted in significant differences in their performance within and between the fields. With these poisons the rodent control success ranged from 23·0–45·6% in the months of August and September and 68·1–93·4% in October to December. Overall reduction in post-control activity of rodents ranged from 47·2–96·1% in different fields with different poison combinations. The rodent control success seemed to be related to the differences in rodent populations, post-control reinfestation rates, timings of poison baiting, stage of crop development, weather conditions and sowing and harvesting operations in the adjoining crop fields. The environmental factors particularly affected the post-control reinfestation of rodents which as compared to the reference fields (0·35 rodents/100 traps/day) was significantly higher in the treated fields (0·56–2·33 rodents/100 traps/day).