Essential oils inhibit stone fruit pathogens in Vietnam and Australia
V.T.T. Dang, V.V.V. Ku, D.H. Vu, V.Q. Mai, E.E. Lazar, S. Hetherington
Program and Abstract. 2007 Australasian Postharvest Conference. Crowne Plaza Terrigal, NSW, Australia. 12 September 2007. 87 p.
2007
บทคัดย่อ
Essential oils inhibit stone fruit pathogens in Vietnam and Australia
Postharvest rot of stone fruit causes major losses during storage and transport. Brown rot caused by Monilinia fructicola is the main concern in Australia. In north westVietnam brown, rot is also a problem and additional loss is caused by Botrytis cinerea and Gloeosporium gloeosporioides. In Australia, the use of registered synthetic fungicides to control postharvest disease is a standard practice but developing 'natural' alternatives is being encouraged. In Vietnam, consignments of fruit are either subject to no postharvest treatment or fungicides are used inappropriately. This study examined the effect of three essential oils from cinnamon, thyme and oregano on the growth of Monilinia, Botrytis and Gloeosporium in-vitro. Results showed that essential oils from cinnamon had a stronger inhibitory effect than the other two oils. It completely inhibited the mycelia! growth of Monilinia and Gloeosporium for 8 days at a concentration of 250ppm while 500 ppm was needed for Botrytis. Thyme and oregano were able to inhibit Monilinia and Botrytis at a concentration of 1000 ppm but did not affect Gloeosporium. Little germination (1-2%) occurred when Monilinia spores were placed on medium amended with 1000 ppm of the three essential oils for 21 hours. No germination was observed for Botrytis placed on media amended with cinnamon oil at concentrations of 500 ppm and above. Thyme did not inhibit the spore germination of Botrytis while oregano inhibited 11% of spores at 1000 ppm. Further work is therefore required to develop a practical system using cinnamon oil to protect stone fruit from postharvest pathogens in both Australia and Vietnam.