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Abstract
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The sweetpotato whitefly, Bemisia tabaci (Gennadius), has become a major threat to agriculture worldwide.
The development of insecticide resistance in B. tabaci has necessitated the exploration of new
management tactics. The toxicity of imidacloprid and buprofezin to various life stages of B. tabaci was
determined in the laboratory. Also, the sublethal effects of both insecticides were studied on demographic
and biological parameters of B. tabaci. Both insecticides were very toxic against first stage larvae
of the pest with LC50 values of 1.0 and 19.3 ppm for buprofezin and imidacloprid, respectively. Toxicities
decreased between successive stages (LC50 values ranging from 1.0 to 2854.0 ppm). The LC50 values of
imidacloprid for adult males, females and eggs were 11.8, 71.6 and 151.0 ppm, respectively. Buprofezin
had no significant effect on adults and eggs. The sublethal concentration of imidacloprid had no
significant effect on demographic and biological parameters of B. tabaci but the maximal value for the
mean generation time (T) (18.8 day) was observed in imidacloprid treatment. Buprofezin significantly
decreased stable population and biological parameters of B. tabaci except it did not decrease the rate of
population increase or the sex ratio of offspring.
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