小麦纹枯病近几年是加重趋势。该病冬前不明显,多在春季发病,一般年份病株率15～30％,严重发生病株率高达60～70％。如小麦播种过早、播量大、施肥结构不合理及春季降雨较多都会导致发病。 一、症状。 主要发生在叶鞘及茎秆上,小麦拔节后,症状逐渐明显。发病初期近地表的受害叶鞘出现黄褐色椭圆形或梭形病斑,以后病斑逐渐扩大,并向内侧发展延及茎部,颜色变深。重病株一、二节间变黑甚至腐烂造成死苗。小麦生长的中、后期,叶鞘上的病斑常形成云纹状花纹,被害的叶鞘与茎秆之间,有时可见 Wheat sheath blight is aggravating trend in recent years. The disease is not obvious in winter, mostly in the spring onset, the general year of diseased plants rate of 15 to 30%, a serious occurrence of diseased plants as high as 60 to 70%. Such as premature sowing of wheat, sowing large, irrational fertilization structure and spring rainfall will lead to more disease. First, the symptoms. Mainly occurs in the leaf sheath and stem, wheat jointing, the symptoms gradually obvious. Early onset of damage to the surface of the sheath appears brown oval or fusiform lesions, after the lesion gradually expanded, and to the medial extension of stem extension, the color becomes darker. Severe strains of one or two black or even decay caused dead seedlings. Wheat growth in the late, leaf sheath lesions often form cloud pattern, the victim of the sheath and the stalk, sometimes seen