Dynamics of Damage from Rhizoctonia Solani in Potato Fields

Abstract

'!he presence of the pathogenic fungus Rhizoctonia solani in potato fields and the expression of damage to plants is often irregular and patchy. It was observed on different soil types that in certain areas a sed- ously damaged potato crop was sometimes followed by a crop that was free of damage. '!his phenomenon was studied in an experimental field where the damage disappeared in only part of the field. '!he results appear to be exceptional: R. solani had not disappeared from the area that was free of damage and verticillium biguttatum, a specific mycoparasite of R. solani, conunonly occurring in agricultural soil, apparently had not played any role.