Life table and budgeting of Plassey borer, Chilo tumidicostalis Hampson (Lepidoptera: Pyralidae)

Field and laboratory experiments were conducted to estimate life table and budgeting of sugarcane Plassey borer, Chilo tumidicostalis during 2015–16. The absolute population of C. tumidicostalis and its natural enemies has been used to prepare age-specific life tables and to determine generation-wise various key mortality factors acting on the population dynamics of the pest. Generation survival, trend indices, ‘k’ values, and other factors influencing the build-up and the decline of the pest population during the crop seasons have been studied. Population dispersal, attack of parasitoids and various other unknown factors were found to have a maximum impact towards mortality of early (expected) as well as the late instar larvae of C. tumidicostalis in different generations. Elevated trend indices were obtained in the second (1.1), third (1.39) and fourth-generation (1.02) of the pests indicated an increase in the borer population during subsequent generations. Declined trend indices were recorded in the first (0.85) and fifth-generation (0.74) population of the pest, which implied a decline in the pest population in the next generation. Information on key mortality factors along with the generation-wise life-table analysis and budgeting will help in generating effective management strategy against C. tumidicostalis .