American Journal of Essential Oils and Natural Products

AUTHOR(S): Akinbuluma Mobolade Dele

ABSTRACT:Synthetic chemicals have undesirable effects on man and his environment, when used in controlling insect pests. Volatile oils from plants possess numerous biological activities against insect pests, but information on the use of volatile oils from Cedrela odorata against stored product insect pests, is scanty. Volatile oils were identified from ethanol extract of Cedrela odorata stem bark using the gas chromatography - mass spectrometry (GC/MS). The effects of six of the standard compounds, each at 1.0% (v/v) namely: Caryophyllene oxide, Ethyl oleate, Ethyl hexadecanoate, Guaicol, Hexanal and Methyl linoleate on mortality, oviposition and repellence of Sitophilus zeamais as well as on germination of maize seeds were determined relative to a synthetic chemical, pirimiphos-methyl and ethanol, as positive and negative control, respectively. All data collected were analyzed using ANOVA and means were separated with the DNMRT at 5% significant level. Twenty-nine constituents were identified in the volatile oil. The most abundant compounds were ethyl hexadecanoate (19.76%), ethyl oleate (17.88%) and methyl hexadecanoate (10.38%) while minor compounds included α-curcumene (0.57%), α-muurolene (0.53%) and spinasterone (0.43%). The compounds tested were better than the control in causing mortality and reducing oviposition by female Sitophilus zeamais. Mortality and oviposition of S. zeamais on grains treated with ethyl hexadecanoate, ethyl oleate and methyl linoleate were not significantly different from those of pirimiphos-methyl. The compounds were repellent to S. zeamais with methyl linoleate, exhibiting the highest. This study revealed that the volatile oils from Cedrela odorata stem bark have potential as biopesticide for Sitophilus zeamais.

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