Leaf Spot Disease of Little Bluestem, Big Bluestem, and Sand Bluestem Caused by Phyllosticta andropogonivora. J. M. Krupinsky, Plant Pathologist, USDA, ARS, Northern Great Plains Research Laboratory, Mandan, ND 58554. D. A. Tober, Range Conservationist, USDA, Soil Conservation Service, Bismarck Plant Materials Center, Bismarck, ND 58502. Plant Dis. 74:442-445. Accepted for publication 22 February 1990. 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, 1990. DOI: 10.1094/PD-74-0442.

A leaf spot disease was found to be widespread in a little bluestem (Schizachyrium scoparium) nursery established at Mandan, ND, from plants collected in North Dakota, South Dakota, and Minnesota. In 1984 through 1987, Phyllosticta andropogonivora was consistently isolated from leaves showing leaf spot symptoms. In 1986, the fungus was also isolated from native prairie little bluestem plants, from nursery and native prairie big bluestem (Andropogon gerardii) plants, and from nursery sand bluestem (A. gerardii var. paucipilus) plants. The fungus was pathogenic to little bluestem, big bluestem, and sand bluestem in several glasshouse inoculations. The fungus, which has not been previously described on little bluestem or sand bluestem, was considered to be the cause of a leaf spot disease. The disease apparently has the potential to reduce forage quality and yield of little bluestem and possibly sand bluestem. With few exceptions, the little bluestem isolates caused more disease symptoms on little bluestem than did isolates from big bluestem and sand bluestem, and the big bluestem and sand bluestem isolates caused more disease symptoms on big bluestem and sand bluestem than did the little bluestem isolates.

Keyword(s): Andropogon scoparius, A. hallii.