Field efficacy of reduced active ingredient zinc phosphide formulation against rodents

A formulation of zinc phosphide with reduced active ingredient (40% concentrate) was evaluated for its rodenticidal activity in wheat, rice and sugarcane crops at farmer fields of Punjab, India. Comparison was made with the existing formulation (80% concentrate) and second generation anticoagulant bromadiolone (0.25% concentrate). Cereal based baits containing different doses of new (1.5, 2.0 and 2.5%) and existing zinc phosphide (2%) and bromadiolone (0.005%) were applied through burrow baiting where Bandicota bengalensis, Mus booduga, Millardia meltada and Tatera indica were the predominant rodents. The reduction in rodent activity was determined based on pre- and post-treatment bait census. Results revealed that 2% and 2.5% bait formulations of new zinc phosphide are as effective as the existing/ recommended zinc phosphide (2%) and bromadiolone (0.005%) bait formulations.