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一、蔓枯病发病症状西葫芦苗期发病,多在茎的下部,病部呈油浸状.后变黄褐色,稍凹陷,表皮龟裂,常分泌出黄褐色树脂状物,严重时病茎折断,导管不变色。成株发病,病菌表皮呈黄白色,枯干,潮湿时变黑褐色,圆形,有不明显的同心轮纹,上生小黑点,病斑扩展至叶面1/3以上时,叶片便干枯。二、病原及发病条件病苗以分生孢子器和子囊壳在病残体及架材上越冬和越夏。分生孢子及子囊孢子借风雨传播,引起田间初次侵染,以后在病斑上产生分生孢子继续传播蔓
First, the incidence of symptoms of gourd Zucchini seedling incidence, mostly in the lower part of the stem, the disease was oil-like. After turning yellow-brown, slightly depressed, cracked skin, often secreted brown resin-like matter, severe disease stem Break, the catheter does not change color. Adult disease, the pathogen was yellowish white, withered, dark brown when wet, round, there is no obvious concentric whorl pattern, black spots on the students, lesion spread to the leaf more than 1/3, the leaves dry . Second, the pathogen and the disease conditions Seedlings in order to conidia and ascus shell disease in the debris and shelves overwinter and summer. Conidia and ascospores spread by wind and rain, causing the initial infection in the field, after the conidia on the lesion continue to spread