Preliminary Study On Incidence Regulation Of Black Spot Disease Of Jujube In Reclamation Area Of Alar

Object: Black spot disease of jujube is the main disease in fruit maturity. In order to control the development of this disease, this study aimed to investigate incidence regulation in reclamation area of Alar. Methods: The incidence regulation including primary infection sources, temporal and spatial dynamic of conidial dispersal, influencing factors of conidia dispersal, relationships between conidia dispersal and disease incidence were observed by capturing airborne technique and survey in field. Stepwise discriminate analysis and stepwise multiple regression analysis were used to find the most important factors which determine the scale of jujube black spot disease. Results: Black spot pathogen Fungi on jujube residues are the primary sources of infection. The conidia initial diffusion was observed in later May and its epidemic was from July to August. The conidia predominant flew within the jujube plant canopy. The daily dynamics of conidia diffusion revealed peak were at 12:00 am. Airborne conidia concentrations show that conidia numbers rise during flowering season, than the peak in fruit expending time. Numbers of conidia fall in mature period. Conidia dispersal were positively correlated with the field disease, air temperature and rainfall. Indoor separation test showed that Alternaria alternate was isolated from fruit skin and skin nearby in bulking stage healthy fruit. It may infect through skin respectively. Fruit wound causing by rain and wind is a possible infection way. We consider that a common cultivar variety—Zizyphus jujuba Mill cv.Junzao has inferior disease resistances to Alternaria alternate compared with Zizyphus jujuba Mill cv.Huizao, another common variety. Disease grew worse when using flood irrigation in jujube orchard. Rainfall in September was one of the most important factors, which affect the epidemic scale of black spot disease. Conclusion: Jujube residues are the primary sources of infection. Conidia dispersal has seasonal dispersal character and it was positively correlated with the field disease. The amount of pathogen fungi, varieties, irrigation, temperature and rainfall codetermine the incidence and epidemic of black spot disease of jujube.