Weller (1988) reported that the microorganism that colonizes roots is ideal for use as a biocontrol agent against soil-borne diseases. Streptomyces griseoviridis is a good example for colonization of plant rhizosphere by actinomycetes. S. griseoviridis is an antagonistic micro- organism dominant in biocontrol of plant diseases such as the fusarium wilt of carnation (Tahvonen, 1988)