Inhibition Of Postharvest Pathogens By Essential Oils And Their Effect On Storage Quality Of Sweet Cherry

Sweet cherry (prunus avium L.) which belongs to the plant family Rosaceae has became an important economic fruit. There were enormous economic losses each year due to postharvest diseases and poor storage and transportation technology. Using ’Labinsi’sweet cherry as the test material, this paper has conducted systematic research on pathogens of sweet cherry, including the isolation, identification and biological characteristics research of pathogens, the inhibition effect of plant essential oil against pathogens, in order to offer the theoretical basis of disease control. In addition, the effect of plant essential oil on sweet cherry was studied. The results are as follows:1 Identification of the pathogens on postharvest sweet cherry fruitsThe pathogens of sweet cherry were isolated and identified in low temperature storage. Pathogenicity of fungal isolates obtained from these samples was tested according to the Koch’s Postulation. The pathogens were identified as Mucor sp., Sclerotinia sclerotiorum, Clonostachys sp., Colletotrichum gloeosporioides2 Biological characteristics of postharvest sweet cherry fruitsSDA medium with lactose as carbon source, beef extract as nitrogen source and dark condition were the best for the growth of Mucor sp., Sclerotinia sclerotiorum. pH=7.0 and dark condition were the best for spore production. SDA medium with KNO3 as nitrogen source, pH=6.0 and light condition were the best for the growth of Clonostachys sp. SDA medium with sucrose as carbon source and KNO3 as nitrogen source,20℃ and dark condition were the best for the growth of Colletotrichum gloeosporioides.3 Inhibition of the pathogens on postharvest sweet cherry fruits by plant essential oilThe MIC, MFC of thyme oil against these four pathogens were≤1000μL/L. The MIC, MFC of clove oil against Mucor sp., Sclerotinia sclerotiorum, Clonostachys sp., Colletotri-chum gloeosporioides were≤500,1000,500, 1000μL/L, respectively. The MIC, MFC of cinnamon oil against Clonostachys sp., Colletotrichum gloeosporioides were≤250μL/L.Compared with contact treatment, fumigation treatment of thyme, cinnamon oil was better against four kinds of tested pathogens and contact treatment of clove oil was better than fumigation treatment. Irreversible inhibition of Mucor sp., Sclerotinia scleratiorum growth couble be caused by exposure to 500μL/L thyme oil as a fumigant in vitro and the incidences of decayed sweet cherry against Mucor sp., Sclerotinia sclerotiorum were 0, 15.67% as a fumigant in vivo, respectively. Irreversible inhibitionof Mucor sp., Sclerotinia sclerotiorum growth couble be caused by exposure to 500μL/L clove oil as contact treatment in vitro and the incidences of decayed sweet cherry against Mucor sp., Sclerotinia sclerotiorum were 21.30%,26.67% as contact treatment in vivo, respectively. Irreversible inhibition of Clonostachys sp. growth couble be caused by exposure to 500μL/L thyme oil as a fumigant,500uL/L clove oil as contact treatment,185μL/L cinnamon oil as a fumigant in vitro and the decay incidence of thyme oil at 750 uL/L as a fumigant, clove oil at 1000μL/L as contact treatment, cinnamon oil at 500μL/L as a fumigant were 0,67%,7.5% in vivo, respectively. Irreversible inhibition of Colletotrichum gloeosporioides growth couble be caused by exposure to 500μL/L thyme oil as a fumigant, 750μL/L clove oil as contact treatment,250μL/L cinnamon oil as a fumigant in vitro and the decay incidence of thyme oil at 750 μL/L as a fumigant, clove oil at 1000μL/L as contact treatment, cinnamon oil at 500μL/L as a fumigant were 19.33%,100%,41.6%% in vivo, respectively.4 Study on the effect of essential oils on postharvest quality of sweet cherryThe results showed that thyme, cinnamon oil at 500uL/L and controlled atmosphere storage with 5% O2+8%CO2 could reduce the respiration intensity of postharvest sweet cherry, inhibit the declining rate of hardness, soluble solid, vitamin C content and the rot rate of sweet cherry stored at (0±1)℃ for 50 days were 10.0%,14.4%,12.4% respectively, thyme and cinnamon oil were much better in improving moisture than controlled atmosphere storage.