Separation，identification and spore germination conditions of the pathogen causing shoot blight on blueberry （Vaccinium spp.）

In 2016，some individuals of blueberry in Zhejiang plant base were dead in the seedling stage. In this study，to identify the pathogenic bacteria，some methods including tissue separation，single spore purification， Koch's postulate，conventional morphological and molecular biology were used. The factors affecting spore germination were also explored，including temperature，pH value，illumination condition，medium component and so on. Results showed that the dead plants were caused by shoot blight，which was induced by ZA1. The colony of pathogen ZA1 was round and white，and the conidium was spindle-shaped，divided into five cells by four true septums，and the intermediate cell was brown，the cells at both ends were colorless. The pathogen ZA1 was identified as Pestalotiopsis clavispora by morphological observation and sequence analysis of rDNA-ITS. Meanwhile，the optimum temperature for spore germination was 30℃，otherwise，lower temperature（ below 20℃） affected germination rate significantly. The adaptability of strain ZA1 spores was very broad，whose pH value could change among pH 3-12. And both light and complex carbon sources were beneficial for spore germination.