The effects on grain yield and some agronomic traits of different disease levels of oilseed rape infected by Leptosphaeria biglobosa was studied by the means of artificial inoculation and natural induction.Significant variations were identified on plant height pod number grain number and thousand-grain weight.Some variations existed among different damage degrees of these traits.The maximum yield loss was up to 50.5%,when the disease level was 5.There were significantly or very significantly negative correl...