苏丹草Sorgum sudauense(Pizer)Stazf是鱼的优质青饲料,年产量占青饲料总量的80％以上。近几年来,因紫斑病(Cer-cospora sorghi Ell Ell et EV.)严重,使苏丹草产量与品质大幅度下降,现将此病发生与防治的调查结果简报如下。 一、症状与危害 此病茎部、叶片和叶鞘先发病,渐向上部蔓延。病叶最初散生针头大小的褐色带有淡黄色的晕圈的斑点。以后病斑呈椭圆、或长条形,病斑也可相互融合成不规则形的大病斑。病斑边缘深紫,中间灰褐,在病斑的反面长出灰色霉层(病菌的分生孢子梗和分生孢子),有的病斑可见隐约云纹。 叶鞘上形成长条、椭圆或不规则形的斑 Sudan grass Sorgum sudauense (Pizer) Stazf is a premium green fodder for fish that produces more than 80% of the total green feed per year. In recent years, due to the severe purple-spot disease (Cer-cospora sorghi Ell Ell. Et EV.) So that Sudan grass yield and quality dropped significantly, now the incidence of the disease and prevention survey results are summarized below. First, the symptoms and endanger the disease stems, leaves and leaf sheath first onset, gradually spread to the upper part. Sick lobe nascent spatter size brown with a halo of yellowish spots. After the lesion was oval, or long strip, the lesion may also be integrated into irregular large lesions. Lesions edge purple, the middle of gray brown, in the opposite of the lesion grow gray mold layer (bacteria conidia and conidia), and some spots visible faint moire. Leaf sheath formation of long, oval or irregular shaped spots