Abstract: An object of the present invention is to provide seeds coated with an antagonistic microorganism, which have high-level disease control effects and high preservation stability. The present invention makes it possible to drastically elevate the survival percentage of an antagonistic microorganism in seeds coated with the antagonistic microorganism by vacuum inoculating seeds with the antagonistic microorganism, drying seeds inoculated with the antagonistic microorganism under low-temperature, low-humidity conditions, or a combination of these methods.

Abstract: Herein provided is a plug mixture for raising seedlings, which contains endosymbiotic Pseudomonads mutualistically colonizing in endorhizosphere, Pseudomnonas fluoresceFPT-9601 and Pseudomonas sp. FPH-9601. Using the plug mixture, soil-borne diseases of crop plants and flowering plants can be prevented, and the producibility of such plants can be increased. The plug mixture contains said two Pseudomonads in an amount of not smaller than 10.sup.5 CFU/g each, and may contain 1-?3-(4-hydroxyphenyl)propanoyl!-2-piperidone in an amount of not smaller than 10 ppm. The two strains are separately added to different plug mixtures, which are then blended to give the intended plug mixture for raising seedlings. To this is optionally added 1-?3-(4-hydroxyphenyl)propanoyl!-2-piperidone. The plug mixture is effective for preventing soil-borne diseases, such as bacterial wilt, fusarium wilt and late blight, of various crop plants.