Toothpick method to evaluate soil antagonism against the white root rot fungus, Rosellinia necatrix

A method was developed to evaluate soil antagonism against the white root rot fungus, Rosellinia necatrix. Toothpicks colonized by the fungus were immersed into hot water to produce an extinction zone (EZ) of the fungus and then inserted into soil from different orchards. The EZ differed to various extents in unsterile soils; however, when soil was sterilized, the EZ disappeared. Using this method, we investigated the mechanism of the hot water drip irrigation method devised to control white root rot. The results showed the involvement of synergism between hot water and soil antagonists in the control measure against R. necatrix.