冬未春初是苦荬菜白粉病发生为害的高峰期,在叶片上布满白色粉状物后,叶片干枯,生长点萎缩,不长新根,不发新叶,植株越长越小,并逐渐枯萎死亡,必须每7～10天叶 Winter is not the beginning of spring is bitter powdery topdressing powdery mildew occurs in the peak, the leaves covered with white powder, the leaves withered, growing point atrophy, not a new root, no new leaves, the longer the plant smaller, And gradually withered death, must be every 7 to 10 days leaves