Effect of Inoculum Concentration and Interrupted Wetness Duration on the Development of Anthracnose Fruit Rot of Strawberry.

Anthracnose fruit rot (AFR) of strawberry, caused by Colletotrichum acutatum, greatly affects production if not controlled. Application of fungicides in addition to the use of less susceptible cultivars are important tools for AFR control. The effects of interrupted wetness duration and inoculum concentration on the development of AFR were evaluated on strawberry cultivars with different levels of susceptibility. Fruit rot and flower blight incidence generally increased with increasing inoculum concentration. 'Camarosa' and 'Treasure' were more susceptible than 'Strawberry Festival' and flowers were more susceptible than immature fruit for most cultivars. Interruption in wetness periods had a significant effect on disease incidence when fruit where exposed to dry periods of 6 h or more compared with 24 h of continuous wetness. The results of this study will be used to refine a disease-warning system to predict AFR outbreaks in Florida strawberry production fields.