Validation of recommended doses of insecticides against sucking pests of BT cotton

Abstract

Comparative efficacy of acetamiprid, imidacloprid and dimethoate at university recommended dose, double the recommended dose and dose used by the farmers was evaluated against sucking pests of Bt cotton. The results revealed that minimum population of sucking pests was observed in dose of acetamiprid used by farmers (6.0 g/10 L of water) and was followed by double the recommended dose of imidacloprid (4.5 ml/10 L of water) and higher dose of dimethoate used by farmers (30 ml/10 L of water). Maximum seed cotton yield (1816.81 kg/ha) was recorded in higher dose of acetamiprid used by farmers @ 6 g/10 L of water and it was at par with imidacloprid @ 9 ml/ 10 L of water (1661.00 kg/ha) and imidacloprid @ 4.5 ml/ 10 L of water, double the recommended dose (1453.00 kg/ha). However, maximum ICBR (1:13.7) was obtained in acetamiprid @ 6 g/10 L of water (higher dose used by farmers) and was followed by acetamiprid @ 3 g/10 L of water (double the recommended dose) with ICBR of 1:9.8. Higher doses performed better than the recommended doses indicating possibility of resistance in sucking pests of Bt cotton.