Applied Studies of Biological Control Techniques on Healthful Chinese Crud Drugs Screening strains for Trichoderma spp. for strong antagonism against ginseng root pathogens and study on their biological characters BIOLOGICAL EFFECT OF ~ 60 Co γ IRRADIATION ON Trichoderma Antagonistic mechanisms of Trichoderma spp. againstPhytophthora nicotianae The antagonism mechanisms and diseases control trials of Trichoderma strain T97 against several plant fungal pathogens in greenhouse Bio-control effect of trichoderma SPP. and its application