Evaluation of an eco-friendly botanical extract against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and its composition

Abstract

The red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), is one of the most damaging grain insect pests in the storage products industry. The acquired resistance to synthetic pesticides and the high toxicity of these compounds on non-target organisms have led to an increase in the search for biopesticides. Thus, the present study aimed to analyze, for the first time, the chemical composition of the extract of Crotalaria stipularia Desv. seeds and its insecticidal activity against T. castaneum adults. Therefore, the crude extract (5 % w/v) of C. stipularia seeds was performed in a 50 mM Tris − HCl pH 8.0. Lectin and secondary metabolites such as flavones, flavonols, xanthones and saponins were detected in the extract. The extract (10 % w/v) of C. stipularia caused 100 % mortality against T. castaneum insects and exhibited moderate deterrent activity, resulting in a 70 % reduction in food consumption compared to their normal intake. Furthermore, the aqueous extract exerted antinutritional effects, interfering with the metabolism of proteins, cholesterol, triglycerides and carbohydrates, and abolished the hatching of eggs of the treated insects. The phytotoxicity test revealed that the extract of C. stipularia is not toxic to non-target organisms, as it did not affect the germination of lettuce (Lactuca sativa) seeds. These results support the search for integrated management strategies for the control of T. castaneum using a new biomaterial obtained from C. stipularia seeds.