The Influence of Pratylenchus penetrans and Temperature on Black Root Rot of Strawberry by Binucleate Rhizoctonia spp.. J. A. LaMondia, Department of Plant Pathology and Ecology, Connecticut Agricultural Experiment Station, Valley Laboratory, Box 248, Windsor 06095. S. B. Martin, Department of Plant Pathology and Ecology, Connecticut Agricultural Experiment Station, Valley Laboratory, Box 248, Windsor 06095. Plant Dis. 73:107-110. Accepted for publication 17 August 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0107.

Strawberry plants (cultivar Honeoye) exhibited symptoms characteristic of black root rot when grown in soil infested with binucleate Rhizoctonia spp. (R. fragariae) anastomosis groups (AG) A, G, and I. Monoxenically cultured lesion nematodes, Pratylenchus penetrans, added to soil at rates of 170, 90, and 17 nematodes per cubic centimeter of soil increased the severity of Rhizoctonia root rot at both 10 and 24 C. Higher nematode levels were more effective in increasing root rot caused by these fungi than were lower levels. Feeder root length was reduced by both pathogens. Root rot in the presence of both pathogens was higher at 24 than 10 C. Binucleate Rhizoctonia AG-I was more virulent than AG-A or AG-G at 10 C, whereas AG-G caused more disease at 24 C than did the other anastomosis groups.