Studies on the Efficacy of Leaf Extract of Balanites aegyptiaca on the Oviposition and Survival of Immature Stages (Larvae and Pupae) of Callasobruchus maculates (F.) on Treated Cowpea Seed

Abstract

The efficacy of Balanite aegyptiaca acetone leaf extract against the survival of Larvae and pupae of Callosobruchus maculatus (F.) on cowpea treated seed was evaluated at the Biological Sciences Department, Bayero University, Kano. Leaf extract from B. aegyptiaca was obtained by extraction using acetone as the solvent and the extract was diluted prior to the experiment. C. maculatus were obtained from IITA in Kano State of Nigeria. The insects were reared in the laboratory. Four different concentrations of the leaf extract (0.5, 1.0, 1.5, and 2.0g) were separately mixed with twenty gram (20g) of cowpea in separate Petri dishes which correspond to (2.5, 5.0, 7.5, and 10.0w/w) respectively. Control treatment was set along. Ten adult pairs of newly emerged C. maculatus were introduced into each Petri dish. Oviposition of the female insect was significantly (p<0.05) reduced on seed treated with higher treatment level of the extract, in comparison with the control treatments. Furthermore the survival of larvae and pupae from the seed cotyledon were also found to be significantly reduced (p<0.005) on seed treated with varying doses of B. aegyptiaca leaf extract. The lower concentration of the extract(2.5%w/w) recorded 41.43% and higher dose recorded 32.94% survival of larvae and pupae from the seed cotyledon in comparison with the control treatments (90.85% and 91.32 %). None of the seeds treated with B. aegyptiaca leaf extract at all level of application recorded similar result with the seeds treated with Actellic dust. B. aegyptiaca leaf extracts was effective against oviposition and survival of larvae and pupae when compared with the untreated control treatment the extract therefore has great potential for use as a plant-based biopesticide for controlling pulse beetle C. maculatus.

Keywords: Balanite aegyptiaca, Acetone leaf Extract, Survival, Immature stages (larvae &pupae),
Callasobruchus maculatus