Relationship of Rhizoctonia solani and Colletotrichum coccodes to Basal Stem Canker of Tomato. William J. Manning, Associate Professor, Department of Plant Pathology, University of Massachusetts, Amherst 01003. Plant Dis. 64:76-78. Accepted for publication 9 March 1979. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-76.

Rhizoctonia solani and Colletotrichum coccodes were associated with a basal stem canker of field-grown tomatoes in Massachusetts. R. solani was most frequently isolated from the early stages of canker development, whereas frequency of isolation of C. coccodes increased with canker age. Under experimental conditions, cortical wounds were necessary for R. solani to cause cankers on stems of tomato transplants. Isolates of R. solani from stem cankers, root lesions, and root surfaces varied in ability to cause cankers, those from stem cankers being most virulent. C. coccodes isolates caused limited canker development. Susceptibility of 16 tomato cultivars to R. solani varied according to cultivar and origin of isolate.