Downy Mildew of cucumber[Pseudoperonospor cubensis(Berk.et Curt.) Rostov.] is one of important problems during producing of cucumber. It is serious harm for people’s health and ecological environment because of using a lot of pesticide to prevent the disease every year. At present, induced resistance is recognized that it is the most potential way of preventing Downy Mildew of cucumber. The study showed that it could make the cucumber plants resistant to Downy Mildew of cucumber when the cucumber seedling w...