Chemical composition of Bessera elegans (Asparagaceae) flower extracts and their insecticidal effect against Melanaphis sacchari Zehntner (Hemiptera: Aphididae)

This study describes the chemical composition and insecticidal effect of the n-hexane (EHBe) and acetone (EABe) extracts of flowers of Bessera elegans Schult. f. (Asparagaceae) against the sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), which is the main pest of sorghum. The gas chromatography-mass (GCMS-) analysis of the EHBe identified 26 chemical compounds, among which triacontane was the most abundant (21.01%). High-performance liquid chromatography (HPLC) of the EABe identified polypheno-lic compounds as major compounds. The toxic effect of EHBe and EABe on M. sacchari was assessed by con-tact bioassays and artificial diet. All of the extracts were toxic to M. sacchari, and mortality was dose-and time-dependent. In the contact toxicity bioassays, EHBe was more effective, eliminating 88% of the insects within 72 h at a concentration of 10,000 ppm. Meanwhile, in the artificial diet bioassays, EABe had the high-est mortality rate (69%) at the same time and concentration. Our results show that EHBe and EABe can reduce the risks associated with synthetic insecticides and therefore be considered a potent source for the produc-tion of botanical insecticides against M. sacchari.(c) 2023 SAAB. Published by Elsevier B.V. All rights reserved.