白粉病是三麦的主要病害。为了解病害引起的损失及其发生规律,1979年进行了观察和试验。 一、病害损失测定 1.发病程度与病害损失:据对宁麦4号小麦测定结果,发病越重,千粒重越轻,平均严重率达30％左右的,千粒重下降6％左右(表1)。 Powdery mildew is the main disease of three wheat. In order to understand the damage caused by disease and its occurrence, the observations and tests were carried out in 1979. First, the loss of disease determination 1. The incidence and loss of disease: According to the determination of wheat Ningmei 4 results, the incidence of heavier, 1000-grain weight lighter, the average serious rate of 30% or so, 1000 grain weight decreased by about 6% (Table 1).