小麦白粉病是高产麦区的一大病害,近年日趋加重,给小麦生产带来严重威胁,为了使小麦生产再上一个新台阶,探讨最佳防治途径,我们从1986年开始,在石家庄地区农科所对白粉病发生规律及规范化防治技术进行研究,现将小麦白粉病发生时期及对产量的影响简述如下: 一、发生部位及症状。小麦白粉病在石家庄地区一般最早发生在4月上旬。初期是侵染茎基部和底部叶片,无效分蘖上也有发生。然后延伸到顶三叶,严重时上到穗部,病斑多在叶片正面。初为针尖大小病斑,后出现白色的丝状层(即分生孢子)逐渐形成面积为1—3mm~2的梭形病斑。白色的丝状层也逐渐变为褐色或灰褐色,上面着生散状黑色小粒 Wheat powdery mildew is a major disease in high-yielding wheat area and has been aggravating in recent years, which poses a serious threat to wheat production. In order to make wheat production reach a new stage and explore the best way to prevent it, we started from 1986 in Shijiazhuang Section of the occurrence of powdery mildew disease and standardized control technology research, now the occurrence of wheat powdery mildew and the impact on the yield as outlined below: First, the occurrence of parts and symptoms. Wheat powdery mildew in Shijiazhuang generally occurs first in early April. In the early stage, the base and bottom of the stems were infected, and ineffective tillers also occurred. And then extended to the top trefoil, severe on the spike, spot more in the leaf front. The beginning of the size of the needle tip lesions, after the emergence of white filamentous layer (conidia) gradually formed an area of ​​1-3mm ~ 2 spindle-shaped lesions. White filamentous layer also gradually turned brown or taupe, with loose black pellets on top