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花椰菜霜霉病在南北地区普遍发生。南方主要危害采种株,对种子产量的影响较大;北方生产田发生严重时,产量有一定损失。花椰菜叶片、花球、花梗和种荚均可受害。叶片形成黄色病斑,边缘不明显,生有黑褐色斑点,叶背面病斑上有黑褐色的斑点,较为明显并稍突起,上有白色霉层,严重时叶片枯黄脱落。花梗受害常发生折断以致枯死,使种荚不能结籽。本病在叶背面产生受叶脉限制的多角形病斑,高湿时散生霜状白
Cauliflower downy mildew occurred in North and South areas. Major harms to the south of the plant species, the greater impact on seed production; serious production fields in the north, the output has a certain loss. Cauliflower leaves, flower bulbs, pedicel and seed pods can all suffer. Leaves form a yellow lesion, the edge is not obvious, dark brown spots, dark brown spots on the back of the leaf spots, the more obvious and slightly protruding, there is white mold layer, serious yellow leaves off. Occurrence of pedicel damage often ruptured, so that seed pods can not seed. The disease produced in the back of the leaves by the limitations of the polygamous lesion, scattered when the wet creamy white