黄瓜霜霉病从温室传到大棚、小拱棚,再传到露地黄瓜上,又从露地秋瓜传回到温室黄瓜上,所以霜霉病终年不断发生。由于霜霉病是气传病害,传播很快,因此发病严重。一茬黄瓜往往要喷化学农药8～12次,不仅成本高,而且污染严重,对人类的健康 Cucumber downy mildew spread from the greenhouse to the shed, a small shed, and then spread to the exposed cucumber, and from the open autumn melon pass back to the greenhouse cucumber, so downy mildew all year round. As downy mildew is a gas-borne disease, spread rapidly, so the incidence is serious. A cucumber is often spray chemical pesticides to be 8 to 12 times, not only high cost, but also serious pollution to human health