Virulence of Phoma lingam to Cabbage. J. M. Bonman, Graduate Research Assistant, Western Washington Research and Extension Center, Puyallup 98371. R. L. Gabrielson, Plant Pathologist, Western Washington Research and Extension Center, Puyallup 98371; P. H. Williams, Professor, and P. A. Delwiche, Graduate Assistant, Department of Plant Pathology, University of Wisconsin, Madison 53706. Plant Dis. 65:865-867. Accepted for publication 10 December 1980. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-865.

Isolates of Phoma lingam obtained from cabbage tissues were differentiated by symptoms on wound-inoculated cabbage cotyledons and by pigment production in vitro. Isolates that produced pigment caused only cotyledonary tissue darkening and limited tissue collapse, did not spread significantly in seedbeds, and produced only superficial lesions on transplanted cabbage. Isolates that did not produce pigment caused cotyledonary tissue collapse and were able to spread in cabbage seedbeds and damage transplanted cabbage grown to maturity. A range of virulence was observed within the latter isolates.

Keyword(s): Leptosphaeria maculans.