Abstract: We investigated the biocontrol potential of the tea produce from spent mushroom substrate compost for the control of strawberry Verticillium wilt caused by Verticillium dahliae, which is in order to make target use of compost tea to the achievement of disease prevention and treatment. In vitro and in vivo experiments were carried out to determine the mechanisms involved in suppression of V. dahliae. Non-sterilized, heat-sterilized and filter-sterilized compost teas were tested on the inhibition of mycelial growth and conidial germination of V. dahliae. Glasshouse trials were conducted to evaluate the control efficiency of compost tea against strawberry Verticillium wilt and plant growth-promoting effect, and to test for the ability of the compost tea to induce the production of defense-related enzymes. The highest percentage of inhibition in mycelial growth and conidial germination was obtained by the non-sterilized compost tea with values of 92.43% and 82.94%, respectively. The inhibitory efficacy was reduced significantly when the tea was heat-sterilized or filter-sterilized. Pot tests indicated that the control effect of Verticillium wilt was 42.23% when strawberry plants were pre-treated with compost tea. There was a significant increase in defense enzymes when the pre-treated strawberry plants were challenged with V. dahliae. The activities of POD and PPO were increased by 45.45% and 39.47% respectively as compared with the control, while the content of MDA decreased by 14.83% on the sixth day after inoculation. It was therefore suggested that the SMS compost tea suppress pathogen through direct inhibition of microorganisms and primed systemic resistance.

Key words: compost tea of spent mushroom substrate (SMS), strawberry Verticillium wilt, induced systemic resistance, action mechanism