Disease Note

First Report of Wild Rice Diseases in Idaho. R. L. Bowden, Department of Plant Pathology, University of Wisconsin, Madison 53706. D. J. Eschen, Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow 83843. Plant Dis. 70:800. Accepted for publication 18 March 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-800b.

Wild rice (Zizania aquatica L.) was imported into Idaho from Wisconsin 30 yr ago and seed from Minnesota was also imported recently. Wild rice disease surveys were done in 1984 at anthesis and at maturity in three commercial fields totaling 50 ha in Benewah County and 20 ha in Benewah Lake. Isolations from stem and foliar lesions yielded the following plant pathogens: Sclerotium oryzae Catt., S. hydrophilum Sacc., Bipolaris sorokiniana (Sacc.) Shoem., Pseudomonas syringae pv. syringae Van Hall, and P. syringae pv. zizaniae Bowden & Percich. Smut caused by Entyloma lineatum (Cke.) Davis was identified by typical symptoms on leaves, culms, and sheaths. All diseases occurred at low incidence (<5%) and severity (<1%) in 1984. The nematode Hirschmanniella gracilis (de Man) Luc & Goodey was isolated at an average of 48/gm dry weight of roots. This is the first report of S. oryzae, S. hydrophilum, E. lineatum, and H. gracilis in the Pacific Northwest and the first report of P. s. pv. zizaniae outside of Minnesota.