Response of Field-Grown Tall Fescue Infected by Acremonium coenophialum to Puccinia graminis subsp. graminicola. R. E. Welty, Agricultural Research Service, U.S. Department of Agriculture, National Forage Seed Production Research Center, Corvallis, OR 97331-7102. R. E. Barker, and M. D. Azevedo. Agricultural Research Service, U.S. Department of Agriculture, National Forage Seed Production Research Center, Corvallis, OR 97331-7102. Plant Dis. 77:574-575. Accepted for publication 29 January 1993. 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, 1993. DOI: 10.1094/PD-77-0574.

Plants of tall fescue cultivar Kentucky 31 infected (E+) or not infected (E–) by the endophyte Acremonium coenophialum were evaluated for reaction to Puccinia graminis subsp. graminicola for 2 yr in field plots. Stem rust was assessed on the modified Cobb scale on five dates in 1991 and three dates in 1992. On each date, stem rust severity in susceptible plants of Kentucky 31 was similar for E+ and E– plants. On the final assessment in both years, the number of plants without stem rust (0% infection) was similar for E+ and E– plants. Based on these results, the presence of A. coenophialum in plants of Kentucky 31 did not influence stem rust severity or the number of stem rust-resistant plants. Thus, the stem rust reaction is not influenced by the presence of this endophyte in tall fescue.