Pea Leaf Roll in Northwestern U.S. Pea Seed Production Areas. Richard O. Hampton, USDA-ARS, Oregon State University, Corvallis. Plant Dis. 67:1306. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1983. DOI: 10.1094/PD-67-1306.