The laboratory evaluation of insecticidal activities and phytochemical analysis of Marrubium astracanicum Jacq. subsp. astracanicum Jacq. against Callosobruchus chinensis (L.) and Callosobruchus maculatus (F.)

Abstract

Callosobruchus spp. as the important pests of legumes and synthetic insecticides are often used to control them. Due to many side effects of synthetic insecticides, the utilization of plant extracts as an alternative control agent against pests has gained interest in recent years. This study was therefore undertaken to determine the insecticidal activity of M. astracanicum Jacq. subsp. astracanicum Jacq. extracts against C. chinensis (L.) and C. maculatus (F.) and the chemical composition of the active extract. The aerial parts of the plant were extracted by using the solvents of various polarities (hexane, n-butanol and water) and two different methods (topical and contact) were applied for the laboratory evaluation of insecticidal activities. The concentration required to kill C. chinensis adults (LC50: 389.18 ppm) after 72 h of topical application using hexane extracts was found to be higher than the concentration required to kill C. maculatus adults (LC50: 324.25 ppm). Similarly, the time required to kill C. chinensis adults (LT50: 56.78 h) was longer than the time required to kill C. maculatus adults (LT50: 50.23 h) in topical application. The GC-MS analysis of the active extract (hexane) showed the presence of longipinane, (E)- (29.61%), palmitic acid (8.23%), hexahydrofarnesyl acetone (6.72%) and neophytadiene (6.68%) as major compounds. The overall results of the current study suggest that M. astracanicum subsp. astracanicum is effective as a botanical insecticide, subject to the field evaluation. & COPY; 2023 SAAB. Published by Elsevier B.V. All rights reserved.