Study On Isolation And Identification Of Pathomycete From Postharvest Fruit Rot Of Sugar Apple (Annona Squamosa L.) And The Control Ofthe Disease

Sugar-apple is a kind of high public awareness of typical tropical fruit withmilky white pulp in color.sweet taste and rich aroma.However,due to the strong physiological metabolism of sugar-apple after harvest,the fruits were easy become soft and rot by fungal infection which result in the loss of the fruit value and seriously affecting fruit quality storage period which has kept it from long-distance transport and selling.Compared with other tropical fruits,there is very little research on the disease of sugar-apple and no report on the development of the disease of sugar-apple.At present,compared with other tropical fruits,there is few researches on the postharvest diseases of sugar apple and there is no relevant report about occurrence regularity.This paper reviewed the research progress of common fungal species and the application and prevention of non-pollution control methods in fruits and vegetables such as chitosan,chitosan oligosaccharide,botanical fungicides,Na2CO3 and NaHCO3,and various combination control methods were evaluated.At the same time,the disease of sugar apple was analyzed and identified and the biology characteristics of host and corresponding drug inhibition were analyzed.The results were as follows:1.Identification of disease symptoms and pathogensSymptoms:The plaque was round in shape,and the surfance was dented.If pressing,the flesh was soft,the central part of infected tissue showed lignite black.The junction of infected part and healthy parts was marked with a water stain,which was characterized by a black and brown conical decay,it took a few days to rot the whole fruit.Pathogenic bacteria was hyphopichia burtonii A.2.The biological characteristics,host range and chemical inhibition test of hyphopichia burtonii APathogenic bacteria colony on a PDA was round in shape,The surface was smooth,sticky and wet.The colony was ivory in colour.,Under the microscope across,branching hyphae with pseudohyphae was found.,The spore was round or oval in shape,with a budding reproductive mode.Some showed beaded structure.The hyphae was white,branching and clustering.,The optimum growth temperature was 25?,The growth of colony was not affected by light,The optimum pH value was 5,The optimum carbon source was glucose,the optimum nitrogen source was peptone;The spore lethal temperature is about 55?;The test showed that the pathogenic bacteria were both broad-spectrum and selective,and the fruit could grow rapidly only if the conditions were suitable.3.Results of experiment disease control and fresh keeping testThe commonly used chemical agents benomyl and chlorothalonil functioned inhibitory to the pathogenic bacteria but did not fuction lethal effect.0.4%of sodium nitroprusside had obvious antibacterial effect,0.2%of boric acid completely control the growth of bacteria..The results of the fresh keeping test showed that both 0.2%and 0.4%of boric acid had a good preservation effect,while 0.4%of sodium nitrate was more effective than 0.2%of sodium nitrate.