Potentiality of some botanical extracts as biopesticides against the maize weevil, Sitophilus zeamais Motsch. (Coleoptera: Curculionidae)

Abstract

Laboratory studies were conducted to investigate the efficacy of some botanicals in the management of Sitophilus zeamais Motsch infesting stored sorghum. The selected plant species were Euphorbia balsamifera Aiton, Lawsonia inermis L. and Mitracarpus hirtus L. Chloroform leaf extracts of the botanicals applied at 6.25, 12.50, 25.00, 50.00 and 100.00 mg ml-1 were used to determine their effect on adult survival, the concentration of total body protein and inhibition of acetylcholinesterase enzyme (AChE) activity in the weevils at 30 ± 2 o C and 70 ± 5% R.H. The botanicals resulted in adult mortalities ranging from 10.00 ± 0.00 to 90.00 ± 5.77%, reduced body protein and significantly inhibited the activity of AChE in S. zeamais. The botanicals tested could serve as biopesticides in the management of S. zeamais infesting sorghum in the storage.