Essential oils as natural sources for the control of Botrytis cinerea: Chemical composition and antifungal effect

The essential oils of cinnamon, clove, bergamot, lemongrass, citronella, rosemary, basil and lemongrass were extracted by hydrodistillation, had their composition determined by gas chromatography coupled with mass spectrometry and were investigated for their potential to restrict Botrytis cinerea cultivar in vitro, a fungus responsible for the gray mold disease that mainly attacks strawberry plants. Their composition was then correlated chemometrically to identify likely compounds that were related to the observed inhibition effects. Five essential oils demonstrated an inhibitory effect on Botrytis cinerea, through the well diffusion method, with the control plate being the plate without the addition of essential oil. Among these, clove, cinnamon and lemongrass showed the greatest action with the lowest inhibitory concentrations (0.85 mg/mL). The best fungicidal effects were for the essential oil of cinnamon (0.85 mg/mL), clove (1.27 mg/mL) and aloysia (2.12 mg/mL). The main correlated compounds were cinnamaldehyde, eugenol, beta-citral and citronellal. Through the analysis of the main components, it is observed that lemongrass essential oil is closer to clove essential oil and, subsequently, to aloysia essential oil, having some compounds in common, among them limonene and citral.