小麦叶锈病、白粉病和条锈病普遍率与严重度间的关系

THE RELATIONSHIPS BETWEEN INCIDENCE AND SEVERITY OF LEAF RUST, POWDERY MILDEW AND YELLOW RUST OF WHEAT

在田间接种条件下,详细地观察了小麦叶锈病、白粉病和条锈病普遍率与严重度之间的关系(I—S关系)。结果表明供试三种病害的I—S关系均可用指数函数描述;在普遍率小于70%左右时,用直线方程拟合效果更好;普遍率大于90%时,对严重度的预测效果较差。分别建立了各病的I—S关系式。小麦生育阶段(拔节期、抽穗开花期、灌浆期)对叶锈病和白粉病I—S关系没有明显的影响,而条锈病的I—S关系在不同生育阶段有一定的差异。文章最后对I—S关系的使用进行了讨论。

The relationships between incidence and severity (I-S) of leaf rust (Puccinia recondita), powdery mildew (Erysiphe graminis) and yellow rust (P. striiformis) were studied throuth inoculation experiments in the field. The results showed that the I-S relationships of these diseases might be described with exponential functions.The I-S relationships also could be described with linear functions when incidence was below 60-70%. I-S relationships were unpredictable when incidences were above 90%. Equations for I-S relationships of the three diseases were built up individually. Wheat growth stages did not affect I-S relationships of leaf rust and powdery mildew evidently, but affected that of yellow rust. It was discussed how to use I-S relationships in disease monitoring.