Role of carvacrol and menthone in maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) management

Insecticides of synthetic origin used indiscriminately to manage insect pest populations are known for genotoxicity, neurotoxicity and teratogenicity in non-target organisms as well as the development of resistance in target insects. These issues have focused insect pest management research towards the use of plant-based chemicals of a volatile nature. In this study, two plant-origin volatile compounds, carvacrol and menthone have been evaluated for their potential insecticidal properties against the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae). These two natural volatile chemicals repelled adults and caused lethality in adults as well as larvae. These two volatile chemicals inhibited acetylcholine esterase enzyme activity in adults when fumigated with sub-lethal concentrations. Both volatile chemicals reduced oviposition potential, progeny production and feeding behavior as well as prolonged the developmental period of the insect. Therefore, it can be concluded that these two natural volatile chemicals can be used in the preparation of volatile chemical-based formulations in the management of maize weevil S. zeamais.