First record and description of Ralstonia solanacearum wilt in patchouli from Yunnan Province, China.
In April 2009, Pogostemon cablin plants in the Xishuangbanna Prefecture of Yunnan Province, China, and Myanmar were infected by a wilt disease. In May, as the temperature increased, the whole plant wilted rapidly. The percentage of diseased plants was up to 70%, sometimes resulting in total crop loss. In the field, the initial symptoms consisted of wilting of one or two upper leaves of six-month-old plants. Approximately 3 days later, the plants often died following the wilting of more leaves. The roots of dead plants turned black. The young plants usually wilted more rapidly than the mature plants. The pathogen was identified as R. solanacearum based on the morphological and physiological characteristics of the isolate, pathogenicity test, and 16S ribosomal DNA analysis. Commelina communis in the pathogenicity test was also infected by the pathogen. This is thought to be the first report of R. solanacearum causing wilt disease on P. cablin in Yunnan, China, and the first report of R. solanacearum on C. communis.