Contact and Fumigation Toxicity of Plant Monoterpenes against Pulse Bruchid, Callosobruchus maculatus (F.) and its Effect on Acetylcholinesterase Activity

Abstract

Background: Callosobruchus maculatus is a major stored-pulse insect-pest and resistance to synthetic insecticides has increased the need for safer alternatives. The monoterpenes from plant volatile compounds are being explored for Insect-pest control. Methods: Six monoterpenes viz., citral, β-citronellol, eucalyptol, geraniol, β-myrcene and thymol were evaluated for contact toxicity, fumigant toxicity and acetylcholinesterase (AChE) inhibition against C. maculatus under laboratory conditions. Result: Thymol and geraniol showed the highest contact toxicity, while citral was most effective as a fumigant. β-citronellol and thymol caused strong AChE inhibition. The study suggests that monoterpenes have potential as eco-friendly alternatives to synthetic insecticides for stored-product pest management.