日本的农业科技人员发现,黄瓜霜霉病的发病率与植株体内的氮糖比有关,如氮糖比小于2,则霜霉病易发生,如果提高氮糖比后则可预防该病的发生。为此,他们将尿素、葡萄糖(或白糖)、水按1∶1∶100的比例混匀,在 Japan’s agricultural science and technology personnel found that the incidence of cucumber downy mildew and plant nitrogen and sugar ratio, such as nitrogen and sugar ratio of less than 2, the downy mildew prone to increase nitrogen and sugar ratio can prevent the occurrence of the disease . To this end, they will urea, glucose (or sugar), water at a ratio of 1: 1: 100 mixing, at