Resistance risk of Magnaporthe grisea to tricyclazole.

The induced resistance of Magnaporthe grisea to tricyclazole was conducted indoor by ultraviolet and MNNG.One low-resistant strain and one mid-resistant strain were obtained through ultraviolet.There were 3 low-resistant and 2 mid-resistant strains through MNNG induce.The EC50 and it′s pertinence of 3 groups strains to tricyclazo1e,prochloraz and azoxystrobin were examined.The results indicated that there were no cross resistence among tricyclazo1e,prochloraz and azoxystrobin.The biologi-cal characristics of resistant strains were examined,including growth rate of fungi,spore amount and pathogenicity.The growth rate of Magnaporthe grisea had no relationship with sensitivity EC50 of strains,maybe it’s decided by its own characteristics.There was a negative correlation between spore amount and the sensitive of strains to tricyclazo1e.The more the strain was sen-sitive to tricyclazo1e,the bigger the spore amount was.There was also a negative correlation between the pathogenicity and the sensitive of strains to tricyclazole.The pathogenicity of resistant strain was more weaker than sensitive strain.Therefore,even though there were resistant strains to tricyclazole in field,but it’s difficult to become superior cluster.