Effect of Insecticidal Schedules on Intermittent Population of Jassid and Whitefly and Yield of Cotton

Field trials were conducted during 1988 and 1989 crop season at the Indian Agricultural Research Institute, New Delhi, to study the impact of different insecticidal schedules on intermittant population of jassid and population build-up in whitefly in American and barbadense eotton nnd dield do seed cotton. Result shows that a 4-spray schedule (dimethoate, monocrotophos, cypermethrin and endosulfan) during less pest population and a 5-spray schedule (dimethoate, monocrotophos, cypermethrin, endosulfan and fenpropathrin) during high pest population were effective in suppressing intermittant population of jassid without build-up in whitefly population beyond economic threshold level and increasing the yield of seed cotton m both the cotton races. Insecticidal schedule consisting of either 4 or 5 sprays of only conventional insecticides was not effective against pest complex of cotton, rather it was disadvantageous to cotton growers to depend on such schedule.