Identification of binucleate rhizoctonia spp. ag-a from strawberry and multinucleate R. solani ag-2-2 from sugar beet in Serbia

Rhizoctonia spp. comprise soil-borne fungi widely distributed in temperate climate worldwide which are annually causing significant yield loses to a range of cultivated plants. A species status of Rhizoctonia spp. has not yet been established and the isolates are classified based on nuclei status as multinucleate and binucleate Rhizoctonia spp., and further divided into 13 anastomosis groups (AG) (AG-1-13) of multinucleate Rhizoctonia and 23 AG (AG-A-W) of binucleate Rhizoctonia. In this paper we are reporting morphological and molecular features of binucleate Rhizoctonia spp. AG-A causing black root rot on strawberry and multinucleate R. solani AG-2-2 causing root and crown rot of sugar beet. During 2015 and 2016 at several strawberry and sugar beet producing areas, plants expressing prominent root and crown necrosis and rot have been observed with disease incidence estimated at 20-30%.