Insecticidal and repellent properties of Baccharis salicifolia essential oil against the stored product pest of Neltuma alba, Riphibruchus picturatus (F.) (Coleoptera: Chrysomelidae: Bruchinae): Chemical composition and mechanism of action

Abstract

The use of essential oils (EOs) represents a promising approach for developing alternatives to synthetic pesticides for pest management in storage facilities has attracted considerable attention due to their demonstrated effectiveness, lower toxicity, and reduced environmental persistence. In this study the EO from Baccharis salicifolia (Ruiz & Pav.) Pers. (Asteraceae) was investigated. A total of twenty-two compounds were identified, with α-phellandrene (a monoterpene) and the sesquiterpenes elemol and spathulenol being the major constituents. The EO extracted from B. salicifolia exhibited strong contact insecticidal activity against Rhipibruchus picturatus (F.), a key pest of Neltuma alba pods under storage conditions. Additionally, the EO demonstrated significant repellent effects against this plague. The study also examined the mechanism of toxicity, revealing that the EO moderately inhibits acetylcholinesterase in vitro, alters the activity of antioxidant enzymes such as superoxide dismutase and catalase, and promotes lipid peroxidation reactions. These biochemical findings were further supported by molecular docking experiments and ADMET database analysis. To the best of our knowledge, this is the first report describing the bioinsecticidal and repellent potential of B. salicifolia EO against the R. picturatus bruchid. The findings underscore its promise as a natural alternative for developing more effective pest control strategies in storage systems.