We investigated the composition og fungal isolates in red clover roots and the susceptibility of red clover cultivars to Sclerotinia trifoliorum, which causes the important disease clover rot. In leaf experiments, the cultivars Jokioinen and Ilte were more susceptible to one of the S. trifoliorum isolates than Betty and Bjursele, while all of them were equally susceptible to two other S. trifoliorum isolates
