黄瓜霜霉病的发病原因主要是保护地的黄瓜,由于环境条件限制,后期个体植株生长较弱、营养不良,上部茎节氮糖比值较低而导致发病。防治方法是将100克尿素和100克白糖加水15公斤充分搅拌溶化后进行叶面喷雾,每亩用药量约100公斤,每7天喷一次,共喷三次、喷施时间,上午 Cucumber downy mildew is mainly caused by the protection of cucumbers, due to environmental conditions, the late individual plant growth is weak, malnutrition, lower nitrogen and sugar ratio of the upper stem section leading to the disease. Prevention and control methods are 100 grams of urea and 100 grams of sugar plus 15 kg of water full of agitation and dissolved foliar spray, the dosage of about 100 kg per mu, spray once every seven days, a total of three spray, spray time, morning