Abstract: A Trichoderma strain of Tk1 was isolated from the root of a medicinal plant Chrysanthemum morifolium "Huangju" in Guangdong. The Tk1 strain was identified to be Trichoderma koningiopsis through morphological observation, rDNA-ITS and EF-1 α sequence analysis. The inhibition rates of T. koningiopsis Tk1 against Fusarium oxysporum and Colletotrichum gloeosporioides in dual culture were 68.5% and 77.1% on PDA plates, respectively, and they could completely or partially cover the colonies of the F. oxysporum and C. gloeosporioides. Thefermentation filtrate showed an inhibition rate of 45.55% to the growth of F. oxysporum. Biological characteristics analysis showed that the optimal carbon source for the growth and conidiation was lactose and glucose, while the optimum nitrogen source was yeast extract. The isolate could grow and sporualte on PDA medium with pH 4-11, and the optimal pH value was 7. Under 12 h light and 12 h dark alteration, the growth rate of the mycelium was the fastest while 24 h consecutive light was the most favorable to its conidiation. The lethal temperature of the strain was 73℃ for 10 min.

Key words: Trichoderma, biocontrol, isolation, identification, antagonistic effect, biological characteristics