油菜菌核病产量损失调查及防治指标研究

通过典型调查和统计分析,油菜千粒重随着菌核病病级的增加而下降,产量损失率随着茎病株率、病情指数的增加而加大。在此基础上建立了千粒重与病情指数、产量损失率与最终病情指数、产量损失率与最终茎病株率回归方程。根据当地近3年油菜平均产量水平、市场价格等推算经济危害允许水平（EIL）,确定油菜菌核病的化防指标为中等偏轻以下发生年不需防治、中等发生年份防治1次、中等偏重以上发生年份防治2次。

Study on Yield Loss Investigation of Sclerrotinia Sclerationum and Its Control Index

Through typical investigation and statistic analysis,the results indicated that the 1000-grain weight decreased with the increase of disease level;yield loss rate increased when the stem disease rate and the disease index increased.Based on the results,three regression equations(the regression equation of 1 000-grain weight and disease index;the regression equation of yield loss rate and ultimate disease index;the regression equation of yield loss rate and ultimate stem disease rate) were formed.The chemical control index of S.sclerotiorum(S.sclerotiorum should not be controlled if it occurred less than mediumly;and should be controlled only once if it occurred mediumly;and should be controlled twice if occurred more than mediumly) were ascertained by EIL,which is caculated by average yield for nearly 3 years,market price and etc.