A serious bacterial disease of sweetpotato caused by Erwinia chrysanthemi in China

摘要

A suspected new disease of sweetpotato was observed at a number of production sweetpotato areas in Guangdong province since 2006. The symptoms were yellow leaves and black water-soaked rot on the bottom of the stems which can extent to the top of the stems gradually,with entire plant collapsed and died in the end. The pathogenic bacteria were isolated from infected vines of sweetpotato. Inoculation on sweetpotato seedlings with this isolate caused the same symptoms as naturally infected plants. The isolate was identified as Erwinia chrysanthemi by pathogenicity,morphological characteristics,culture patterns,physiological and biochemical reactions,and 16S rDNA gene sequences. This is the first report of bacterial stem and root rot of sweetpotato in China.