Toxic Effects of Methanolic Extracts of Plants Leaves on the Mortality and Enzymatic Parameters of Callosobruchus maculatus Fab. (Coleoptera: Bruchidae) Juveniles

This study was conducted in the laboratory to evaluate the effect of leaves extract of three botanicals on the biochemical parameters of insect pest of stored beans, Callosobruchus maculatus. The results of the qualitative phytochemicals revealed the presence of different metabolites such as tannins, saponins, cardiac glycosides, phenolic compounds, flavonoids, alkaloids etc. The toxic effect of methanolic leaves extracts of Lasianthera africana, Hippocratea africana and Uvaria chamae on the mortality and biochemical parameters after treatment against C. maculatus was evaluated. The result showed that treatment of the insects with these extracts significantly increased mortality in C. maculatus. There was a significant inhibition of the enzymatic activities of the digestive enzymes (such as amylase and invertase) in the treated larvae. The transaminase enzymes (AST and ALT) were found to be reduced in the insect after treatment (33.2 and 42.6) while the result of the phosphatase (ACP and ALP) enzyme activity  showed a potent inhibitory effect of the leaves extract, which was more pronounced in ALP (75.8%) than ACP (31.8%).