Five hundred strains of actinomycetes were screened for inhibitory activity against the phytopathogenic fungi; Alternaria alternata, Botryotinia fuckeliana, Colletotrichum acutatum, Colletotrichum gleosporioides, Corticium sasaki, Cylindrocarpon destructans, Fusarium oxysporium, Magnaporthe grisea, Phytophthora infestans, Phytium ultimum, and Thanatephorus cucumeris. The strain CNU-A91231 (Korea Agricultural Culture Collection #20938) showed a strong activity against the phytopathogenic fungi and it was identified as Streptomyces griseofuscus based on the sequence of 16s rDNA. Practical and simple media for the strain S. griseofuscus CNU-A91231 was developed at the conditions ($28^{circ}C$ and pH 6 with aeration) for efficient bacterial growth. Alanine, glutamine, proline and ammonium ion were good nitrogen sources for the bacterium. Addition of the major salts including Na, Cl, Ca, P, K, and Mg into molasses did not increase the growth of S. griseofuscus. Addition of fertilizers containing amino acids significantly enhanced growth of the bacterium. The optimal medium was formulated as molasses + 1% of glutamate fermentation waste powder. All the conditions and components used in this study did not affect the antifungal activity of S. griseofuscus. The bacterium and the medium in this study can be used as a bio-antifungal agent for plant farming.