Rhizoctonia solani: taxonomy, population biology and management of rhizoctonia seedling disease of soybean

Rhizoctonia solani, the most important species within the genus Rhizoctonia, is a soilborne plant pathogen with considerable diversity in cultural morphology, host range and aggressiveness. Despite its history as a destructive pathogen of economically important crops worldwide, our understanding of its taxonomic relationship with other Rhizoctonia-like fungi, incompatibility systems, and population biology is rather limited. Among the host of diseases it has been associated with, seedling diseases inflicted on soybean are of significant importance, especially in the soybean growing regions of North America. Due to the dearth of resistant soybean genotypes, as well as the paucity of information on the mechanisms of host-pathogen interactions and other molecular aspects of pathogenicity, effective management options have mostly relied upon a combination of cultural and chemical control options. The first section of this review summarizes what is currently known about the taxonomy and systematics, population biology and molecular genetics of R. solani. The second section provides an overview of the pathology and management of rhizoctonia root and hypocotyl rot of soybean, a seedling disease of importance in North America.