霜霉病俗称“烘病”、“跑马干”等,是花椰菜的主要病害,发生普遍。主要危害叶片,其次是茎、花梗、种荚。自幼苗至成株期均可发病。高湿、多雨,易于发病。发病轻重常与病毒病、细菌性黑腐病轻重有关。发病高峰期在9月份。一、症状识别该病主要为害叶片,多在植株下部叶片发病,叶正面出现淡绿色至淡黄色的小斑点,扩大后呈黄 Downy mildew commonly known as “roasted disease ”, “horse race ” and so on, is the main disease of cauliflower, common occurrence. The main hazard leaves, followed by stems, pedicels, seed pods. From seedling to adult stage can be disease. High humidity, rainy, prone to disease. The severity of the disease often associated with viral disease, bacterial black rot severity. The peak incidence in September. First, the symptoms identified The disease is the main damage leaves, leaves more in the lower part of the plant disease, pale green to pale yellow spots on the front of the leaves, expanded yellow