Fusarium equiseti GF191 as an effective biocontrol agent against Fusarium crown and root rot of tomato in rock wool systems

Six isolates of plant growth-promoting fungi (PGPF), non-pathogenic Fusarium oxysporum, and five isolates of bacteria were tested in hydroponic rock wool systems as potential biocontrol agents of Fusarium crown and root rot (FCRR) of tomato caused by Fusarium oxysporum f. sp. radicis-lycopersici (FORL). PGPF Fusarium equiseti proved the most effective organism in controlling FCRR, and the reduction rate by F. equiseti against FCRR was consistently high and significant in four experiments. The numbers of colony-forming units of FORL per gram fresh weight of stems were significantly reduced (P=0.05) in plants treated with F. equiseti. Stem extracts from F. equiseti-treated and pathogen-challenged plants significantly inhibited the germination and germ tube length of FORL microconidia. Moreover, stem extracts from F. equiseti-treated plants (not treated with pathogen) significantly inhibited the germination of FORL microconidia and production of FORL budding-cells.