Abstract: The kiwifruit bacterial canker caused by Pseudomonas syringae pv. actinidiae is one of the most devastating disease. Wind, rain and wounds are considered as the main influencing factors and the ways of canker disease transmission. It was of great significance for the prevention and control of the distribution of the pathogen in the orchard and the spread of the infection. Based on this, in this study, we mainly relied on the method of direct extraction of total DNA after isolation and purification of bacteria, using the specific primers ACT1/ACT2 and PsaF1/PsaR2 to identify the main distribution of Pseudomonas syringae pv. actinidiae in kiwifruit; and determine the initial infection of ulcer pathogens and latent sites, the path of initial infection and transmission by scanning electron microscopy and combined with different occured time of Pseudomonas syringae pv. actinidiae. The results showed that the main pathogens of the canker were found in the main vines, main branches, collateral branches, new shoots and leaves of aboveground part. The distribution of the topsoil and roots was very low. At the same time, it was found that the number of canker disease in leaf wound was much larger than that of other intact regions, which was the primary infection point. Pseudomonas syringae pv. Actinidiae have two peaks which are Spring and Autumn, however, there are just a few in the plant tissues in summer and winter. The research were carried out to lay the foundation for the next step in the study of the mechanism of infection and field control.

Key words: kiwifruit, kiwifruit bacterial canker, Pseudomonas syringae pv. actinidiae, pathogen distribution