Population dynamics of Bemisia tabaci on different host plants and its chemical control.

The population dynamics of Bemisia tabaci (Gennadius) on cotton, soybean, peanuts and corn, and its chemical control were preliminarily investigated in 2001 in Langfang City, Hebei Province. The results indicated that during growing stage of hosts, the population of Bemisia tabaci increased continually and up to a peak around on 22nd August, then gradually decreased. There were significant differences among the population densities of Bemisia tabaci on different hosts, the order of density was cotton soybean peanuts corn. Only a few adults but no eggs and nymphs were found on the corn plant. Three insecticides, imidacloprid, buprofezin and beta cypermethrin were applied to control the pest, their effects for adult and nymphs were ranged from 20 07% to 33 19%, 20 62% to 44 88% and 4 05% to 6 78%; 51 91% to 64 46%, 54 30% to 63 99% and 16 73% to 26 97%, respectively.