Insecticidal properties of Leaf extract of Lamium purpureum (Lamiaceae) against Maize weevils Sitophilus zeamais (Coleoptera: Curculionidae).

Abstract

Insecticidal activity of Leaf extracts of Lamium purpureum was evaluated as; contact toxicants, fumigant and F1 progeny production inhibitors to Maize weevil Sitophilus zeamais. The leaves of L. purpureum were collected around Sharada area Kano by hand picking and identified at herbarium of the Department of Biological sciences, Bayero University Kano. They were washed with clean water, dried under shade, grounded into fine powder using pestle and mortar. The extracts were obtained by cold percolation using ethanol as a solvent and four extract concentrations were prepared using 50% Dimethyl Sulfoxide (DMSO) solution. S. zeamais were obtained from infested Maize grains at Abubakar Rimi Market Kano, identified by its morphological appearances and reared under ambient conditions (32±0.640C, 68±3% R.H and 12L: 12D photoperiods) in the laboratory. All bioassays were carried out in small transparent plastic containers (4cm height and 6cm diameter) in triplicates. Data generated were subjected to Analysis of Variance using SPSS (version 20) means were separated at 5% level by Turkeys tests. Results obtained indicate that leaf extract of L. purpureum were effective as contact toxicant, fumigant and inhibitor to First Filial (F1) progeny generation of S. zeamais. Hence leaf extracts of L. purpureum has potential to be use as control agent of Maize weevil S. zeamais infesting stored food products. The findings of this study reveal the usefulness of L. purpureum as biopesticide, as such its incorporation into traditional storage pest management system is recommended.