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玉米大小斑病俗称斑点病,是玉米栽培区发生较普遍的重要病害。我省盆地内以小斑病为主,山区以大斑病为害较重。夏秋多雨季节常导致严重为害,由于叶片早枯影响产量。一、症状识别两病常在田间混合发生,主要侵害叶片,也可侵害叶鞘、苞叶等。大斑病:在玉米整个生育期均可发生,抽穗后发病重。病斑在叶片上少而大,发病初期呈水渍状青灰色小斑点,逐渐沿叶脉向两端扩展,病斑边缘暗褐色,中央为淡褐色的梭形大病斑,一般5—10厘米,宽1—1.5厘米。发病重时,病斑愈合,连成片,常使叶片破裂或枯死。天气潮湿,病斑上长出灰黑色霉层,即病菌的分生孢子梗和分生孢子。
Maize spot spot disease commonly known as spot disease, corn cultivation area is more common and important diseases. The main spot in our province basin is small spot disease, and the big spotted spot disease in mountainous area is heavier. Summer and fall rainy season often lead to serious damage, due to the impact of early crop leaves yield. First, the symptoms of two diseases often occur in the field of mixed occurrence, the main violations of the leaves, but also against the sheath, bract and so on. Great spot disease: Corn can occur throughout the reproductive period, severe onset after heading. Small and large lesions on the leaves, early onset showed water stains like small gray spots, and gradually extended along both sides of the veins, lesion edge dark brown, the central light brown fusiform big spot, usually 5-10 cm , 1-1.5 cm wide. Occurrence of severe disease, lesion healing, even into a film, often rupture or withered leaves. The weather was wet, gray spots on the black mold layer, that is, the germ conidiophores and conidia.