Previous View
APSnet Home
Phytopathology Home


Ecology and Epidemiology

Pathogenicity on Wheat of Pyrenophora tritici-repentis Isolated from Bromus inermis. J. M. Krupinsky, Plant pathologist, U.S. Department of Agriculture, Agricultural Research Service, Northern Great Plains Research Laboratory, P.O. Box 459, Mandan, ND 58554; Phytopathology 77:760-765. Accepted for publication 16 October 1986. 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, 1987. DOI: 10.1094/Phyto-77-760.

Twenty-seven isolates of Pyrenophora tritici-repentis from smooth bromegrass, an alternative host, were tested for virulence on wheat and smooth bromegrass. Detached seedling leaves of wheat and smooth bromegrass were inoculated to compare bromegrass isolates with wheat isolates in individual tests involving five wheat and three smooth bromegrass cultivars. Leaves were visually assessed for percentage of necrosis and lesion length. Although all isolates caused symptoms on wheat and smooth bromegrass, the smooth bromegrass isolates varied in their ability to cause disease symptoms on wheat. Most smooth bromegrass isolates caused disease symptoms on wheat similar to those caused by wheat isolates, but some caused fewer disease symptoms than the wheat isolates. Smooth bromegrass isolates selected for high and low virulence levels in the detached leaf tests were compared in two additional detached leaf inoculations and in glasshouse inoculations with whole plants. The two additional detached leaf inoculations and the glasshouse inoculations with whole plants confirmed the results obtained with the initial detached-seedling leaf inoculations. In both types of inoculations, bromegrass isolates of P. tritici-repentis had virulence levels comparable to those of wheat isolates.

Additional keywords: Drechslera tritici-repentis, leaf spot disease, Pyrenophora trichostoma, tan spot, yellow spot.