Chemistry and insecticidal potential of bay leaf essential oil against stored grain pest of wheat

Abstract

A laboratory experiment was conducted to study chemistry and insecticidal activity of bay leaf oil, its fractions and isolated compounds against stored grain pest of wheat i.e.Tribolium castaneum Herbst. Bay leaf essential oil extracted from dried and powdered bay leaves was subjected to column chromatography to have its fractions. Extensive column chromatography of polar fraction yielded Eugenol and 7, 7 Dimethyl-3-methylene bicyclo [2.2.1] heptan-4-ol which were identified by spectroscopic techniques. Bay leaf oil was tested for its insecticidal activity at five different concentrations in the range 4-12 mg g-1respectively against F1 generation of red rust flour beetle adults. Maximum inhibition was observed at 12 mg g-1concentration. The activity was both time and concentration dependent. The fractions of bay leaf essential oil and the compounds isolated were tested at 4mg g-1 concentration. Polar fraction was found to be more active as compared to nonpolar fraction as 100 and 53.1% mortality was obtained on 30th day for polar and nonpolar fractions, respectively. Comparison of eugenol and 7, 7 Dimethyl-3-methylene bicyclo [2.2.1] heptan-4-ol showed complete mortality on 33rd and 35thday respectively , which revealed that adults of T. castaneum were more susceptible to eugenol.The results indicated that bay leaf essential oil may have potential to control stored grain pest, T. castaneum.