Bioefficacy of plant derivatives on the repellency, damage assessment and progeny production of the cowpea weevil, <i>Callosobruchus maculatus</i> (F.) (Coleoptera: Bruchidae)

  • K. Murugan Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore -641046, India. E-mail:


A laboratory experiment was conducted to investigate the efficacy of different plant derivatives that affect the development of the cowpea weevil, Callosobruchus maculatus fed on cowpea, Vigna unigulculata seeds. The leaf extracts of the aromatic plant, Anisomeles malabarica and Azadirachta indica (neem) were evaluated for their repellency, damage assessment and progeny production of C. maculatus. The results revealed that the extracts of the two plant species caused a considerable reduction in the number of weevils. The combination of neem seed kernel extract and leaf extracts of A. malabarica was the most effective in checking the insect infestation and allowing the least number of F1 adults emerging from the seeds over the other treatments. Acetone extracts of leaves of A. malabarica were more toxic to adult beetles compared to ethanol plant extracts. It was concluded that the botanical products acted as insect antifeedant and the order of repellency of  the two plant leaf and kernel extracts on cowpea weevil were: combination of neem seed kernel extract + A. malabarica leaf extract > neem > A. malabarica.

Keywords: Callosobruchus maculatus, Anisomeles malabarica, Azadirachta indica, Repellency, Damage assessment, Progeny production
Section: Residual Insecticides - Synthetic and Botanical