Aim: To assess the effect of several commercial essential oils samples Australian lemon myrtle (Backhousia citriodora), cinnamon bark (Cinnamomum zeylanicum), oregano (Origanum vulgare), thyme oil (Thymus vulgaris), clove bud (Eugenia caryophyllata), valerian (Valeriana officinalis) and Australian tea tree oil (Melaleuca alternifolia) on mycelium growth and spore germination of Monilinia fructicola. The effectiveness of lemon myrtle essential oil as a fumigant for the control of brown rot in nectarines was evaluated.
Methods and results: Monilinia fructicola exhibited a different level of sensitivity to each tested essential oil with results suggesting that the essential oils provide excellent control of the pathogen with respect to mycelium growth and spore germination at very low concentrations, whereas for others higher concentrations are needed to reduce significant fungal growth. In vivo application of lemon myrtle essential oil effectively reduced the incidence of M. fructicola on noninoculated fruit. Fumigation of nectarines following inoculation did not reduce the incidence of brown rot in comparison with the inoculated control treatment. No evidence of phytotoxicity on the fruit was recorded.
Conclusions: Lemon myrtle essential oil exhibited the strongest antifungal activity against M. fructicola, in vitro and to a lesser extent, under in vivo conditions.
Significance and impact of the study: The results demonstrate that lemon myrtle essential oil, in particular, has potential as an antifungal agent to control M. fructicola.
© 2011 NSW Industry & Investment, Australia. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.