Virulence, vegetative compatibility and ISSR analysis of Fusarium oxysporum f.sp. cucumarinum DETECTION OF DEFOLIATED STRAIN OF VERTICILLIUM DAHLIAE Comparison of Vegetative Compatibility Diversity of Cryphonectria parasitica from Wild and Cultivated Chestnut and Molecular Detection of Mating-type of the Pathogens from Wild Chestnut Transmission of dsRNA in Cryphonectria parasitica and it‘s Affecting Factors STUDY ON VEGETATIVE COMPATIBILITY OF SPHAEROPSIS SAPINEA IN CHINA