Effect of previous crop on soil populations of Burkholderia solanacearum, bacterial wilt, and yield of tomatoes in Taiwan.
Three field experiments were conducted to evaluate populations of B. solanacearum [Ralstonia solanacearum] and the occurrence of tomato bacterial wilt in soil left fallow, and following crops of cowpea, aubergine and rice. The bacterial population declined after cowpea and rice, but not after aubergine. The population also declined after soil was left fallow, suggesting that a suitable host plant is required to maintain the bacterial population. The AUDPC (based on the incidence of wilted tomato plants) was significantly (P<0.05) higher following aubergine than following cowpea and rice for 3 experiments. Yields of cowpea, aubergine and rice were not affected by the presence of R. solanacearum in the soil. Tomato yields were significantly (P<0.05) lower following aubergine than following rice. In the greenhouse, bacterial populations decreased when soil was cropped to rice under permanently flooded conditions.