Fumigant antifungal activity of plant essential oils and components from West Indian bay (Pimenta racemosa) and thyme (Thymus vulgaris) oils against two phytopathogenic fungi

Commercial plant essential oils obtained from 26 plant species were tested for their antifungal activity against Phytophthora cactorum and Cryponectria parasitica. Good antifungal activity against P. cactorum was achieved with the essential oil derived from thyme (Thymus vulgaris) and bay (Pimenta racemosa) at 28 x 10(-3) mg/ml air concentration. Inhibition rates of bay and red thyme were 69.1% and 100%, respectively, at 28 x 10(-3) mg/ml air concentration. In a test with C. parasitica, the inhibition rates of bay and red thyme oil were 75.2% and 100%, respectively, at 28 x 10(-3) mg/ml air concentration. The inhibition rate of cade (juniperus oxycedrus) essential oil was 63.0%, but other oils were <= 40%. Analysis by gas chromatography-mass spectrometry led to the identification of 17 and 20 compounds, respectively, in the oils of bay and red thyme. The antifungal activity of the identified compounds was tested individually using standard compounds. Phenol and alcohol compounds were generally more toxic than hydrocarbons. Copyright (C) 2008 John Wiley & Sons, Ltd.