Bioinsecticidal Activity of Eucalyptol and 1R-Alpha-Pinene Rich Acetonic Oils of Eucalyptus saligna on Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae)
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Health and Environmental Research
Abstract
Exploration of plants, animals, microbes and their products for green pesticides have been the mainstay of modern
agriculturalists. Plant bioactive oils have been utilized in formulation of green pesticides, which are less toxic, least deleterious
on biocontrol agents, readily biodegraded and have no or few ecological effects as compared to synthetic equivalents. This study
evaluated the bioinsecticidal activity of Eucalyptol and 1R-Alpha-Pinene rich acetonic essential oils of dry leaves of the Sydney
Blue gum (Eucalyptus saligna Smith) on common granivorous maize weevil. Fresh leaves of Eucalyptus saligna were harvested
and the essential oils extracted from its dry powder by hydrodistillation. The chemical composition of the essential oil was
analyzed by tandem GC/MS. Twelve components were identified, and the main components were Eucalyptol (34.36%) and
1R-alpha pinene (17.92%). Acetonic essential oils of 2μL, 4μL, 6μL and 8μL in 1ml acetone were used in contact toxicity,
fumigant and repellent bioassays. In contact toxicity, 8μL/ml oil exerted a rapid effect on the weevils giving 100% mortality in
the first day of exposure; 6μL/ml achieved 100% mortality 96 hours after treatment. Both fumigant and repellent activities
showed a gradual increase in insect mortality and repellency with time of exposure as the concentrations of the essential oils were
increased; 100% repellency was achieved at 8μL in the second hour and this remained constant with time. The lowest repellency
of 20% was obtained at 2μL. In fumigant toxicity, the highest mortality was 70% recorded at 8μL on the third day of exposure.
The results indicated that the acetonic essential oil of dry Eucalyptol and 1R-Alpha-Pinene rich Eucalyptus saligna leaves can be
developed into a bioinsecticide for controlling maize weevil as a repellent, toxicant and fumigant candidate.
Description
Keywords
Insecticide, Bioactive, Fumigant, Contact Toxicity, Repellent, Extraction
Citation
Adupa, E., & Kagoya, S. (2018). Bio-insecticidal activity of eucalyptol and 1R-alpha-pinene rich acetonic oils of Eucalyptus saligna on Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae). J. Health Environ Res, 4, 153-160. doi: 10.11648/j.jher.20180404.15