白粉病是露地、保护地及全区蔬菜基地黄瓜上的重要病害,在黄瓜的整个生育期均可发生,主要危害茎、叶和果实,多从植株下部老叶开始发病。病害流行时间长,蔓延速度快,发生逐年加重,轻者减产30%~50%,重者减产70%以上,甚至绝收,严重影响黄瓜生产。白粉病病害流行性强,在空气相对湿度52%~75%,气温20℃~25℃时有利于此病的发生。本试验通过在黄瓜叶面喷施不同浓度的75%百菌清WP,探讨75% Powdery mildew is an important disease on the open field, the protected area and the vegetable base cucumber in the whole region. It can occur during the whole growth period of the cucumber. The main hazards are stems, leaves and fruits, and more diseases begin from the lower leaves of the lower part of the plant. Disease epidemic long time, the spread of fast, increasing year by year, the light output reduction of 30% to 50%, heavy output reduction of more than 70%, or even off, a serious impact on cucumber production. Powdery mildew disease epidemic, the relative humidity in the air 52% to 75%, temperature 20 ℃ ~ 25 ℃ is conducive to the occurrence of the disease. This experiment by spraying different concentrations of 75% chlorothalonil WP in the cucumber leaves to explore the 75%