Fecha de publicación: 24/09/2021 Fuente: Wipo Tobacco Agriculture The invention discloses nano-selenium-synthesized active bacterial liquid of pseudomonas fluorescens, a preparation method for the nano-selenium-synthesized active bacterial liquid and application of the nano-selenium-synthesized active bacterial liquid and belongs to the technical field of microbes and microbial preparations. The nano-selenium-synthesized active bacterial liquid of the pseudomonas fluorescens, disclosed by the invention, is a mixed solution, which is prepared through subjecting the pseudomonas fluorescens to biological fermentation to synthesize nano-selenium and then preparing the mixed solution from the pseudomonas fluorescens and the nano-selenium synthesized by the pseudomonas fluorescens. The pseudomonas fluorescens is pseudomonas fluorescens KBD-1. The strain is preserved in China General Microbiological Culture Collection Center of China Committee for Culture Collection of Microorganisms (CGMCC) on August 31, 2020, and the preservation number of the strain is CGMCC No. 20567. The nano-selenium-synthesized active bacterial liquid of the pseudomonas fluorescens, disclosed by the invention, has a relatively good prevention and treatment effect on viral diseases of crops and provides a new microbial resource for preventing and treating of the viral diseases of the crops; and in addition, the nano-selenium-synthesized active bacterial liquid also has a growth promoting effect on the crops, and the effect is remarkable.