Study On The Pathogenic Mechanism & Control Of Spoilage Fungi On Postharvest Strawberry

The planting area and output of strawberry in China rank the first in the world.Due to the physiological characteristics of strawberry and the limitations of preservation technology,transportation and storage conditions in China,it is easily decayed during storage and transportation of strawberry,moreover,the economic loss caused by its rot is enormous.In order to provide the basis for the prevention and treatment of microbial diseases during storage,strawberry(Fragaria × ananassa Duch.)cultivar named “meiguixiang” was used from Shijiazhuang,Hebei Province,the species of pathogenic fungi,their ways of postharvest diseases infection routs and the antibacterial effects of different antimicrobial agents on them were studied.The species of pathogenic fungi of strawberry in this area was studied.Four kinds of pathogenic fungi were isolated from the postharvest strawberry,which were Rhizopus stolonifer,Botrytis cinerea,Penicillium sp.and Aspergillus niger.The dominant pathogenic fungi were Rhizopus stolonifer and Botrytis cinerea.To find out the characteristics of the pathogenic fungi for facilitating the control of the storage conditions reducing the incidence of postharvest strawberry,the condition of the fungi the fruit carried in the field,the ways of postharvest fruit infection,the effect of temperature on mycelial growth rate of pathogenic fungi and the effects of fruit storage temperature on the fungal pathogenicity were studied.The result showed that pathogenic fungi attached on the surface of strawberry fruit in the field,would further infect the strawberry fruit when condition was suitable.Whether the strawberry fruit was damaged or not is the key factor to affect the pathogenicity of the pathogenic fungi,so does the storage temperature.Rhizopus stolonifer and Aspergillus niger would infect strawberry under high temperature,Botrytis cinerea would infect strawberry under both low and high temperature,the pathogenicity of Penicillium sp.was weak and a common pathogenic fungi.To provide the theoretical basis for the preservation of postharvest strawberry,the antibacterial agents were selected,according to the characteristics of pathogenic fungi.Three kinds of antibacterial agents were selected,which were natamycin,clove bud oil and cinnamon oil,respectively.Meanwhile,the minimal inhibitory concentration was determined.The minimum inhibitory concentration of natamycin on the four kinds of pathogenic fungi(Rhizopus stolonifer,Botrytis cinerea,Penicillium sp.and Aspergillus niger)was 0.02%,0.04%,0.02%,0.02%,the minimum inhibitory concentration of clove bud oil was 0.05%,0.01%,0.01%,0.03% and the minimum inhibitory concentration of cinnamon oil was 0.03%,0.01%,0.01%,0.03%,respectively.