Mutation breeding of resistant streptomyces strain S89 and its inhibiting effect on Botrytis cinerea

4 mutation strains resistant to procymidone, namely, US-1, US-2, US-3, US-4, were screened out through the combination method of UV irradiation and medical cultivation. Inhibition activities of US-1 and US-3 were more significant than their parental strains, inhibition activities of US-2 and US-4 were significantly lower than that of parental strains. Co-action of US-1 whose inhibition activity was strongest and procymidone to botrytis cinerea was studied. Results showed that when 7 shares of US-1 mixed with 3 shares of procymidone its diameter of inhibition zone was 21.97mm, its control effect in vitro on Botrytis cinerea reached 77.68%, obviously more than that of US-1 or procymidone alone.