STUDY ON THE ANTAGONISM OF TRICHODERMA SPECIES ON CANKER PATHOGEN FUNGI OF POPULAR Inhibiting Effects and Mechanism of Trichoderma Strains to Cytospora chrysosperma Pathogenic Differentiation and Genetic Diversity of Cytospora chrysosperma in China Expression of Zinc Finger Protein Gene in Populus alba×P.berolinensis in the Infection Process by Cytospora chrysosperma Colony Characteristics and Genetic Diversity of Cytospora chrysosperma Strains from Ten Provinces in China