大蒜叶枯病系真菌性病害,主要危害叶片。染病初期,从大蒜叶尖开始逐渐向叶茎发展,并由植株下部向上部蔓延。病斑初为苍白色圆形小斑点,后逐渐扩大变成灰褐色,呈椭圆形不规则状,病害严重时,可 Garlic leaf blight is a fungal disease, the main hazard leaves. In the early stage of infection, garlic leaf gradually began to leaf stem development, and spread from the lower part of the plant to the upper part. Lesions initially pale white spots, and gradually expanded into a brown, oval-shaped irregular, severe disease may be