A microorganism selected from the group consisting of Bacillus sp. ITB090 (NITE BP-01725), Bacillus sp. ITB100 (NITE BP-01726), and Bacillus sp. ITB105 (NITE BP-01727), or a mutant strain derived from these strains, is used to control plant disease, control nematodes, promote plant growth, and the like.