山东省小麦纹枯病为害损失及防治指标的研究

通过44个品种83块麦田小麦纹枯病为害损失的测定,明确小麦纹枯病可引起小麦显著减产。病级1～4级,穗粒数降低依次为3.39％、4.68％、5.97％、15.99％,但差异并不显著。千粒重降低依次为2.15％、5.74％、10.53％、18.66％,减产依次为7.21％、12.22％、25.05％、37.72％,千粒重降低是减产的主导因素。同一病级的为害损失,品种间有明显的差异,表现出耐病和敏感的不同,稻茬小麦损失大于玉米茬小麦。小麦群体病株率(X_1)和病情指数(X_2)与产量损失率(L)的关系符合二次曲线:L=0.2072X_1-8.0747×10~(-5)X_1~2-1.4937(n=67,R=0.7181),L=0.4346X_2-3.4835×10~(-4)X_2~2-0.8787(n=67,R=0.7530)。防治适期在小麦返青拔节期3月15日前后。小麦纹枯病防治指标商榷为病株率15％,或病情指数4％。

SOME STUDIES ON THE YIELD LOSSES AND CONTROLLING THRESHOLD OF SHEATH BLIGHT OF WINTER WHEAT IN SHANDONG PROVINCE

Eighty three winter wheat fields of 44 cultivars were investigated, to calculate the yield losses of sheath blight disease. It showed that sheath blight could affect yield significantly. Percentage decrease of thousand kernel weight were 2.15%, 5.74%, 10.53% and 18.66%, and yield losses were 7.21%, 12.22%, 25.05% and 37.72% of 1-4 disease grade, respectively. The decrease of thousand kernel weight is the most important factor related to the yield losses. Under the same grade of infection, there were differences between varieties or stubbles in the yield losses, and the relation between disease incidence (X₁) or disease index (X₂) and yield losses (L) was L=0.2072X₁-8.0747×10^-5X₁²-1.4937(n=67,R=0.7181^**) or L=0.4346X₂-3.4835×10^-4X₂²-0.8787(n=67,R=0.7530^**).This study indicate that the optimal time of controlling this disease is about 15th March, and the ET is 15% disease incidence or 4% disease index.