Abstract
BackgroundThe insecticidal activities of essential oils from seeds of five botanicals Tetrapleura tetraptera, Annona muricata, and Aframomum melegueta and leaves of Eucalyptus globulus and Ficus exasperata were evaluated as biopesticides against the storage pest of cowpea Callosobruchus maculatus (Fabricius). The oils were applied at the concentration of 1 ml/kg, 3 ml/kg, and 5 ml/kg of cowpea seeds mixed evenly. The experiment was laid out in a completely randomized design. The parameters assessed include the percentage of mortality, oviposition, adult emergence, seeds damaged, weight loss, and germinability capacity of the protected seeds.ResultsThe results from the study showed that the effectiveness of the essential oils was dependent on application rates and time of exposure. In the treated cowpea seeds, A. melegueta essential oil was the most effective with 50% lethal concentration (LC50) value of 2.42 ml/kg and 95% lethal concentration (LC95) value of 4.86 ml/kg when compared to the other treatments as indicated by the application rate which caused 50% and 95% mortality of cowpea beetles. A. melegueta essential oil at the concentration of 5 ml/kg achieved 100% mortality of C. maculatus at 48 h of application. Cowpea seeds treated with 5 ml/kg of E. globulus essential oil significantly reduced (P < 0.05) oviposition compared to the other treatments. Cowpea seeds treated with 5 ml/kg of A. muricata essential oil reduced adult emergence (3.67) and weight loss (0.59). The cowpea seeds treated with essential oils at different concentrations had no significant (P > 0.05) adverse effect on seed germination after 120 days of storage.ConclusionBased on the findings of this study, the essential oils could be explored as an alternative bio-pesticide to synthetic insecticide in the protection of stored cowpea against C. maculatus.
Highlights
The insecticidal activities of essential oils from seeds of five botanicals Tetrapleura tetraptera, Annona muricata, and Aframomum melegueta and leaves of Eucalyptus globulus and Ficus exasperata were evaluated as biopesticides against the storage pest of cowpea Callosobruchus maculatus (Fabricius)
The result showed that there were no significant differences in adult mortality of C. maculatus on cowpea seeds treated with the essential oils of the five botanicals
Mortality was highest (26.67%) on cowpea seeds treated with 5 ml/kg of A. melegueta essential oil and the lowest (6.67%) mortality was observed on seeds treated with 1 ml/kg of T. tetraptera essential oil
Summary
The insecticidal activities of essential oils from seeds of five botanicals Tetrapleura tetraptera, Annona muricata, and Aframomum melegueta and leaves of Eucalyptus globulus and Ficus exasperata were evaluated as biopesticides against the storage pest of cowpea Callosobruchus maculatus (Fabricius). Approaches aimed at controlling attack by insect pests have relied heavily on the use of synthetic insecticides (Isman 2006) These synthetic chemicals are associated with shortcomings such as the emergence of resistant strains of pests, elimination of natural enemies and non-target species, environmental health hazard, and contamination of foods with chemicals (Ileke et al 2013). The current study was designed to evaluate the insecticidal activity of essential oils from seeds of Tetrapleura tetraptera, Annona muricata, and Aframomum melegueta and leaves of Ficus exasperata and Eucalyptus globulus for the control of C. maculatus on cowpea seeds
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
