Disease Note

Occurrence of Verticillium dahliae on Barley. D. E. Mathre, Department of Plant Pathology, Montana State University, Bozeman 59717. Plant Dis. 70:981. Accepted for publication 29 May 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-981c.

In July 1985, near Aberdeen, Idaho, barley plants (Hordeum vulgare L. ‘Hazen’) were observed with symptoms typical of those associated with Cephalosporium stripe, i.e., longitudinal chlorotic leaf stripes with brown vascular bundles. The barley plants were growing in a field previously cropped to potatoes. Isolations from symptomatic tissue, however, consistently yielded colonies of Verticillium dahliae Kleb. Pathogenicity tests showed that this isolate could infect and cause symptoms in barley, wheat (Triticum aestivum L.), and oats (Avena sativa L.), as well as in the dicots potato (Solanum tuberosum L.) and tomato (Lycopersicon esculentum Mill.). Although the ability of V. dahliae to colonize roots of barley and wheat has been previously reported (1), these crops generally have been considered immune because of lack of foliar symptoms. Whether this isolate of V. dahliae is unique in its ability to attack monocotyledonous plants is unknown. Its occurrence on monocots suggests that their use as rotation crops to control Verticillium wilt may be compromised where this isolate exists.