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随着棚室蔬菜种植面积的不断增加,油麦菜的种植面积也在加大,目前正是北方大棚油麦菜的生产季节。而霜霉病是保护地油麦菜生产中的主要病害,分布广泛,发生普遍,一般病株率30%～55%,明显影响产品质量,严重地块病株率达到80%～100%,多数叶片因病坏死,显著影响田间生产。发病症状此病从作物的幼苗到收获各阶段都可以发生,以成株期受害较重,主要为害叶片,由外叶向心叶蔓延。初始时在叶片产生淡黄色近圆形至多角形病斑,以后在叶背病斑上长
With the greenhouse growing area of vegetables growing, lettuce planting area is also increasing, it is the northern greenhouse lettuce production season. The downy mildew is the main disease in the production of lettuce in the protected area. It is widely distributed and occurs generally. The average diseased rate is 30% ~ 55%, which obviously affects the quality of the products. The rate of diseased plants in severe land reaches 80% ~ 100% Leaf necrosis due to illness, significantly affect the field production. Disease symptoms The disease from crop seedlings to harvest all stages can occur to adult heavier victims, the main damage leaves, from the outer leaves to the heart leaf spread. The initial pale yellow near the leaves to a polygonal lesion, later in the leaves on the long spots