[Objective] Biocontrol strains against cucumber downy mildew were screened out to lay the basis for biological control of Pseudoperonospora cubensis on cucumber and development of biological agents. [Method] Control efficiency and growth-promoting effects of biocontrol strains of cucumber downy mildew were studied through greenhouse and field experiments. [Result]Greenhouse experiment results showed that after the artificial was inoculated into downy mildew pathogen for 20 d,7 of 34 strains of bacteria coul...