Imazalil Seed Treatment Reduces Common Root Rot and Increases Yield of Barley Under Commercial Conditions. T. J. Herrman, Fremont County Extension Agent, St. Anthony, ID 83445. R. L. Forster, and J. M. Martin. Professor, Division of Plant Pathology, Department of Plant, Soil, and Entomological Sciences, University of Idaho Research and Extension Center, Kimberly 83341; and Associate Professor, Department of Plant and Soil Sciences, Montana State University, Bozeman 59717. Plant Dis. 74:246-247. Accepted for publication 19 October 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0246.

The efficacy of imazalil (Nuzone 10EC) seed treatment for controlling common root rot caused by Bipolaris sorokiniana in barley (Hordeum vulgare) was evaluated in large-scale field trials in Fremont County, Idaho, at six sites in 1985 and three sites in 1986. The control seeds of barley cultivars Steptoe and Klages were treated with carboxin and thiram (Vitavax 200 at 2.6 ml/kg) to control loose smut. The imazalil treatment was the Vitavax 200 treatment at the same rate plus Nuzone 10EC at 1.0 ml/kg. Isolations from 173 diseased subcrown internodes of plants in the control and imazalil treatments in 1986 yielded 106 isolates (61%) of Bipolaris but no Fusarium spp. Seed treatment with imazalil significantly (P = 0.05) lowered disease severity in the subcrown internode, increased grain yield 6%, and increased test weight compared to the control treatment.

Keyword(s): chemical control.