First report of bacterial wilt caused by Ralstonia solanacearum on Roselle in Taiwan.
In April of 2012, a wilt disease appeared on seedlings of roselle (Hibiscus sabdariffa) cv Chiada 1 at the Chungpu Township of Chiayi County in Taiwan. Mature plants were free from this disease. Leaves appeared weak and drooping when they were still green, followed by collapse of the whole plant a few days later. Browning of vascular and pith tissues was evident, especially at the base of the stem. A whitish mass of bacteria oozed from the cut end of diseased stems, suggesting that bacteria might be the cause of this disease. Based on morphological, physiological and molecular investigations (PCR assay) and pathogenicity tests, the causal agent was identified as R. solanacearum. This is thought to be the first report of R. solanacearum on roselle in Taiwan.