Efficacy of botanical leaf extracts as anti-feedants against Riptortus linearis (Fabricius) and their potential in sustainable black gram (Vigna mungo) production

Abstract:

How effectively can plant-derived compounds replace synthetic insecticides in protecting black gram from pod-sucking pests? This research evaluated the anti-feedant properties of aqueous leaf extracts from four botanicals Azadirachta indica (neem), Calotropis gigantea (calotropis), Vitex negundo (vitex), and Eucalyptus globulus (eucalyptus) against Riptortus linearis (Fabricius), a major pod-sucking pest of black gram (Vigna mungo). Three concentrations (10%, 15%, and 20% w/v) were tested using choice and no-choice feeding bioassays under controlled laboratory conditions at the National Autonomous University of Mexico, Mexico City, during March-September 2023. The experimental layout followed a randomized complete block design with five replications per treatment. Among all extracts, neem at 20% concentration recorded the highest feeding deterrence index (89.4%), followed by vitex at 20% (76.5%) and calotropis at 20% (68.1%). Eucalyptus showed moderate anti-feedant activity, with the 20% treatment achieving a 61.8% deterrence index. Leaf area consumption was lowest in neem-treated groups across all concentrations, and a clear dose-dependent response was observed for each botanical. Statistical analysis through one-way ANOVA and Duncan’s multiple range test confirmed that differences between treatments were significant (p<0.05). These results point to neem and vitex leaf extracts as promising botanical alternatives for managing R. linearis in black gram cropping systems, offering a reduced environmental footprint compared to conventional chemical pesticides.