Toxicity of chlorpyriphos with pre-treatment of lufenuron on Helicoverpa armigera (Hubner) and other insects in cotton.

Impact of chlorpyriphos with predose of lufenuron was studied against Helicoverpa armigera and other insects of cotton under field conditions. Chlorpyriphos (4 g a.i./l) alone and chlorpyriphos with pretreatmentof lufenuron (255 and 290 ppm) significantly reduced the damage of both American bollworm and spotted bollworm to intact fruiting bodies (squares and bolls). However, chlorpyriphos (4 g a.i./l) alone demonstrated its superiority over all other treatments with respect to bollworm damage in shed intact fruiting bodies, flowers, green and left over and pickable bolls including seed cotton yield. With respect to non-target pests, lufenuron failed to manage grey weevil, red cotton bug in cotton ecosystem. Similarly, higher seed cotton yield was recorded in chlorpyriphos (4 g a.i./l) as compared to all the other treatments.