黄瓜霜霉病又称 “跑马干 ”，来势凶猛，蔓延迅速，是影响黄瓜产量最重要的叶部病害之一，病情发生时，一般可减产 20％～ 30％，严重时黄瓜不到半架就拉秧。 一、霜霉病的症状 苗期、成株期均可发病，主要危害叶片，子叶受害初呈褪绿色黄斑，扩大后变黄褐色，真叶叶缘或叶背 Cucumber downy mildew, also known as “horse race”, ferocious, rapid spread, is one of the most important leaf disease affecting cucumber yield, when the disease occurs, the general reduction of 20% to 30%, severe cucumber less Raise the shelf half. First, the symptoms of downy mildew Seedlings, adult disease can occur, the main hazard leaves, early cotyledons damage was faded green macular, expanded to brown, true leaf margin or leaf back