Phytochemical Profile and Evaluation of the Insecticidal Potential of Bessera elegans Root Extracts Against Melanaphis sorghi

Sorghum (Sorghum bicolor L. Moench) is one of the most important cereal crops in Mexico due to its extensive cultivation and use in human nutrition, livestock production, and the biofuel industry. However, its productivity is severely affected by the sorghum aphid, Melanaphis sorghi Theobald, 1904 (Hemiptera: Aphididae), a major pest of this crop. Its control relies primarily on synthetic chemical insecticides, whose intensive use has led to environmental impacts and health risks, prompting the search for more sustainable alternatives. In this study, the insecticidal activity of root extracts from Bessera elegans was evaluated against apterous adults of M. sorghi using artificial diet bioassays at different concentrations and exposure times. Chemical characterization of the extracts and the active fraction was carried out using high-performance liquid chromatography (HPLC) and gas chromatography coupled to mass spectrometry (GC–MS). The methanolic extract exhibited the lowest LC50 value (2562 ppm), indicating the highest insecticidal potency, while the acetone extract achieved the highest maximum mortality (98%) at the highest tested concentration. Fractionation of the methanolic extract allowed the identification of fraction BeF1 as the most active, with 94% mortality at 1000 ppm. Chemical characterization indicated a predominance of polyphenolic secondary metabolites, mainly flavonoids and lignans. These results highlight the potential of B. elegans as a natural alternative for the integrated management of the sorghum aphid.