Biological Control of Rhizoctonia Root Rot of Snap Bean with Binucleate Rhizoctonia-like Fungi. J. E. Cardoso, Graduate Student, Department of Plant Pathology, North Carolina State University, Raleigh 27695. E. Echandi, Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27695. Plant Dis. 71:167-170. Accepted for publication 31 May 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0167.

Eleven isolates of binucleate Rhizoctonia-like fungi (BNR) and one isolate each of R. zeae, Trichoderma hamatum, and T. harzianum were studied as potential biocontrol agents of root rot of snap bean caused by R. solani in the greenhouse and field. Isolates of BNR reduced (P = 0.05) disease incidence and disease severity in four greenhouse experiments. Four selected isolates of BNR and the two isolates of Trichoderma species were then screened in soils naturally infested with R. solani. Four field experiments were conducted at two locations. Selected isolates of BNR significantly (P = 0.05) protected bean seedlings from Rhizoctonia root rot in one or more experiments. One BNR isolate (BN-160) significantly (P = 0.05) protected snap beans from Rhizoctonia root rot in all field experiments. Isolate TC-1 of T. harzianum protected bean seedlings in only one field experiment. Results indicate that isolates of BNR show potential as biocontrol agents of Rhizoctonia root rot of snap bean.