Abstract

Soil baiting using the highly susceptible Fragaria vesca clone VS1 was used to assess the persistence of infectivity of Phytophthora fragariae (causal organism of strawberry red core root disease) in naturally infested soil held under a variety of storage conditions and in drainpipe columns exposed in the field. The fungus was detected on all sampling dates during three years in soil samples held at -1 and +3C , more consistently in those that were wet or moist than in those stored dry. At 15C infectivity declined markedly in wet and dry samples but increased in moist samples during the second year before declining markedly in the third year. At 30C infectivity declined rapidly in all samples and was not regained after transfer to 3C . Infectivity was detected on all sampling occasions in soil in the drainpipe columns where it fluctuated markedly, declining in summer then rising in autumn.