Evolution of Effective and Economical Spray Schedules Based on Spray Initiation Against Bollworm Complex in Cotton

To evolve the most effective and economical measures of crop protection for the management of bollworm complex in American cotton under north Indian conditions, six spray schedules based on six criteria of spray initiation have been evaluated. Spray initiation level at 50% flowering stage, which incidentally coincided with the peak squaring stage has been found to be the most economical and effective criterion to start with the spraying operations. A spray schedule S₃ (deltaphos, triazophos, cyhalothrin, quinalphos and phosalone) in which synthetic pyrethroids were alternated with conventional insecticides, was economical and the most effective.