Chemical composition and insecticidal properties of Cinnamomum aromaticum (Nees) essential oil against the stored product beetle Callosobruchus maculatus (F.)

BACKGROUND: Cinnamomum aromaticum is a widely used cooking ingredient in South Asian countries. In this study the essential oil of C. aromaticum was tested against the stored product beetle Callosobruchus maculatus . The objective was to identify the natural compounds with insecticidal properties in the essential oil of C. aromaticum with a view to its potential use as an alternative to synthetic pesticides. RESULTS: The chemical composition of the hydrodistilled bark essential oil of C. aromaticum was analysed by gas chromatography/mass spectrometry, and cis ‐cinnamaldehyde (53.90%) was found to be the principal constituent. The surface film and fumigation toxicities and repellency activity against C. maculatus were evaluated. The extracted oil showed 94.44% mortality against adult C. maculatus through the surface film bioassay. The LD 50 values were 27.56 and 23.16 µg cm −2 after 24 and 48 h of exposure respectively. The regression equations were calculated as Y = 0.39 + 3.20 X and Y = 1.25 + 2.75 X respectively. In the fumigation bioassay the LD 50 value was 434.69 µg cm −2 after 24 h of exposure, with the regression equation Y = 0.87 + 1.57 X . It was also found that the extracted oil contained compounds that had a dose‐dependent protective effect on egg hatching and adult emergence. CONCLUSION: The results obtained from this study suggest that the toxicity and insecticidal activity of C. aromaticum are attributable to its essential oil, which could be used as a biodegradable and natural bioprotectant for controlling stored product pests.