Survival of Ralstonia solanacearum in infected tissues of Capsicum annuum and in soils of the state of Pernambuco, Brazil

The survival of Ralstonia solanacearum A1-9(Rif) race 1 phylotype I was studied in ten different soil types in the absence of the host plant as well as in infected tissues of the stem and root of bell peppers buried in the soil at 0, 5, and 15 cm. The survival time of R. solanacearum A1-9(Rif) in the ten soil types ranged from 42 up to 77 days. Among the chemical and physical characteristics of the soil, clay content, residual moisture, and available water were positively correlated, and pH was negatively correlated, with survival time, population size at 42 days, and area under the population curve. The pathogen survival differed significantly in relation to the plant tissues, but not with respect to the incorporation depth of the infected tissues. The root tissue of bell pepper supported a larger bacterial population at 7 and 21 days (5 x 10(4) and 3.1 x 10(4) CFU g(-1) tissue, respectively) compared with the stem tissue (0.35 x 10(4) and 0.48 x 10(4) CFU g(-1) tissue, respectively) and also had a larger area under the population curve. On the other hand, the stem tissues presented a greater decomposition rate and pH compared with the roots. In conclusion, the different types of studied soils as well as the infected bell pepper tissues were considered potential primary sources of R. solanacearum inocula, but only for a short period.