小麦纹枯病是小麦上的常发性病害。由于发生部位隐蔽,很容易错过防治适期,每年都造成较大的产量损失。小麦纹枯病前期的典型症状是在近土面的叶鞘上形成椭圆形病斑。病斑长2～5mm,边缘褐色,中部灰白,有时破裂。后期在茎秆和叶鞘上形成云纹状病斑,轻则造成穗小、粒少、粒轻,重则形成死苗、白穗。小麦纹枯病的防治适期在拔节前病菌未侵入茎 Wheat sheath blight is a common disease on wheat. Due to the hidden parts, it is easy to miss the appropriate period of control, resulting in a larger annual yield loss. The typical symptom of early wheat sheath blight is the formation of oval lesions on the leaf sheath near the soil surface. Lesions 2 ~ 5mm, brown edge, central gray, and sometimes rupture. Later in the stalks and leaf sheath formation of cloud-like lesions, ranging from the spike is small, less grain, light grain, weight is formed dead seedlings, white spike. Preventing and curing of wheat sheath blight in the pre-jointing pathogen did not invade the stem