Demographic features and population projection of resistant and susceptible populations of Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

Colorado potato beetle (CPB) is the most devastating insect-pest of potato in America, Asia and Europe. Injudicious use of insecticides for management of this pest has resulted in resistance to all major groups of insecticides. Keeping in view the importance of inducing susceptibility in CPB management, fitness parameters of susceptible CPB population were calculated in comparison with normal field populations. For this purpose, Agria cultivar was used for rearing of Colorado potato beetle under controlled conditions. Susceptible popualtion was raised for more than 3 years before the study. While, field population was collected and F-2 was used for the life table study. The life table study of lab susceptible and field collected population showed that the lab susceptible population had significantly less intrinsic rate, fecundity, survival and other population parameters than the field collected population. The calculated population parameters for the field population were 0.12 day(-1) for the intrinsic rate of increase (r), 1.13 day(-1) for the finite rate of increase (lambda), and 71.07 offsprings/female for the net reproductive rate (R-0), and they were significantly higher than the parameters of lab susceptible population (r = 0.10 day(-1), lambda = 1.10 day(-1) and R-0 = 38.43 offsprings/female). The increased biotic potential of CPB in the field can be attributed to the widespread use of neonicotinoids like imidacloprid. After detailed study, such insecticides, that have tendency to enhance the biotic potential of insect-pests, can be banned for better management of notorious insect-pests like CPB.