The occurrence and pathogenicity of uni- and binucleate Rhizoctonia and Pythiaceae fungi among conifer seedlings in Finnish forest nurseries

Uni- and binucleate Rhizoctonia and Pythiaceae fungi were isolated from roots of dieback seedlings. Only binucleate Rhizoctonia strains were present in the roots of healthy seedlings. In pathogenicity tests, uninucleate Rhizoctonia sp. were pathogenic and binucleate Rhizoctonia spp. non-pathogenic. Pythium ultimum var. ultimum and Phytophthora undulata were the only Pythiaceae fungi that killed 12-week-old seedlings.