Resmi S. Nair, Sheeja V.R. and Sajeena Muhamed S.
Abstract
The pesticidal potential of aqueous and methanolic flower extracts of Sterculia foetida (L). was evaluated against the pulse beetle, Callosobruchus chinensis (L), a major pest of stored legumes. Adult beetles were monitored daily for seven days to determine percentage mortality and calculate LD50 values. Both extracts produced significantly high mortality, however, mortality was markedly higher in the methanolic extract treatments. While the control group exhibited complete survival, confirming the strong pesticidal activity of the plant extracts. The efficacy of the extracts was clearly dose-dependent, with higher concentrations causing significantly greater toxicity to C. chinensis than the lower doses. Biochemical analyses revealed marked physiological disruptions in treated insects, indicated by substantial reductions in total body protein and glycogen levels compared to the untreated control. These changes suggest interference with essential metabolic pathways necessary for insect survival. Phytochemical screening showed seven bioactive components in the crude aqueous extract-alkaloids, steroids and terpenoids, flavonoids, coumarins, cardiac glycosides, saponins, and quinines-and eight in the methanolic extract, including alkaloids, tannins, phenols, steroids and terpenoids, flavonoids, coumarins, cardiac glycosides, and saponins These results demonstrate that S. foetida flower extracts possess significant insecticidal activity and biochemical effects on C. chinensis, suggesting their promise as eco-friendly alternatives for stored-grain pest management