Comparative demographic analysis of sub-lethal effects of Calotropis procera extract and some insecticides on Bemisia tabaci (Genn.)

Abstract

The sweet potato whitefly, Bemisia tabaci (Genn.) (Hem.: Aleyrodidae), is a major pest of agricultural and greenhouse crops worldwide. In this study, we used the age-stage two-sex life table to evaluate sub-lethal effects of the botanical extract taken from Calotropis procera (Asclepiadaceae) on B. tabaci and compared these effects with those obtained from exposing the pest to the four synthetic pesticides, abamectin, imidacloprid, diazinon and pymetrozin. The toxicity of the chemical insecticides and C. procera extract on adult whiteflies was assayed using the leaf-dip method. The exposed whiteflies showed significant differences in the net reproductive rate (R0), intrinsic rates of increase (r), finite rate of increase (λ) and mean generation times (T). The lowest amounts of R0, r, λ and T parameters were observed in diazinon (2.373, 0.036, 1.036, and 24.590) and pymetrozin (2.455, 0.036, 1.036, and 25.281), respectively. Additionally, the parameters obtained from the age-stage two-sex life table method were compared to those of traditional female age-specific life table. Statistical analysis revealed no significant difference among parameters obtained from the two life table methods. Results of this study implies on potential of C. procera extract for control of B. tabaci comparable to chemical pesticides.