Effect of different nozzles droplet sizes of insecticides on the persistent toxicity against larvae of cabbage butterfly Pieris brassicae (Linn)

The present investigation was undertaken at Division of Entomology, SKUAST-Kashmir, Shalimar during the year 2014. In this experiment effectiveness of hollow cone nozzle and full cone nozzle in controlling cabbage butterfly was evaluated keeping in view the persistent toxicity, relative residual toxicity, LC50, LT50 value and order of relative efficacy of three insecticides namely Dichlorvos 76 EC, Malathion 50 EC and Quinalphos 25 EC at three different concentrations. The three concentrations of insecticides were 0.1, 0.05 and 0.025% for Dichlorvos, 0.14, 0.07 and 0.035% for Malathion and 0.07, 0.035 and 0.0175% for Quinalphos.It was found that Malathion proved to be least toxic to the 2nd instar larvae of cabbage butterfly followed by Quinalphos and Malathion. Persistent toxicity of all the three insecticides was more in hollow cone nozzle as compare to full cone nozzle.