This invention is to provide microbial pesticides that can control plant disease damages by spraying the microbial pesticides, which contain filamentous fungus Verticillium lecanii having suppressant effect on the growth of plant pathogen, onto plants such as fruits and vegetables, and to provide soil borne improvement agents which contain filamentous fungus Verticillium lecanii, and exert effect on improving the soil borne by applying to soil borne. By applying filamentous fungus Verticillium lecanii, preferably strains having an ability of colonization on plant surface, and/or strains having an ability of colonization on plant root surfaces and/or in rhizosphere to plants as microbial pesticides, the growth of plant pathogens as well as insect pests adhering to plants can be significantly suppressed. Furthermore, by giving them to soil borne, the growth of pathogens in plant rhizomes and the rhizosphere thereof can be suppressed, and pathogens are not developed in the soil borne even after the transplantation, therefore, the soil borne can be improved.