Abstract: We investigated the control effect of different insecticides on Bemisia tabaci MED field population in tomato fields under different agricultural landscapes in Yunnan Province. The toxicity of four insecticides to B. tabaci MED in tomato fields under four agricultural landscapes was determined by leaf dipping method in laboratory. Field control effects of these four insecticides were evaluated by spraying method. The results showed that B. tabaci MED were most sensitive to abamectin in summer and winter, while the LC₅₀ of summer tomato fields in suburban, flower, river and mountain landscapes were 2.61, 3.65, 4.84 and 2.75 mg·L^-1, respectively. The LC₅₀ of winter tomato fields in flower, river and mountain landscapes were 2.03, 3.11 and 1.64 mg·L^-1, respectively. The field control effects of the four insecticides against B. tabaci MED in tomato fields from high to low were abamectin > sulfoxaflor > thiamethoxam > bifenthrin in summer and winter. The sensitivity of B. tabaci MED population to insecticides was significantly affected by landscape types. B. tabaci MED was more sensitive to insecticides in suburban and flower landscapes, but less sensitive to insecticides in river landscape. The tested insecticides have a good control effect on B. tabaci MED in tomato fields under suburb and flower landscapes. Abamectin and sulfoxaflor can be preferentially selected in chemical control of B. tabaci MED.

Key words: Bemisia tabaci, insecticide, toxicity, field control effect, agricultural landscape.