VIEW ARTICLE

Directional Growth and the Perennial Characteristic of Ustilago striiformis in Poa pratensis. Clinton F. Hodges, Assistant Professor of Horticulture and Agronomy, Departments of Horticulture and Agronomy, Iowa State University, Ames 50010; M. P. Britton, Professor of Botany, Flathead Valley Community College, Kalispell, Montana 59901. Phytopathology 60:849-851. Accepted for publication 15 December 1969. DOI: 10.1094/Phyto-60-849.

Studies on directional development of Ustilago striiformis var. poae in Poa pratensis following coleoptile infection revealed mycelium in primary crowns and subsequent development of smutted rhizomes and tillers. Similar mycelial colonization of crowns, rhizomes, and tillers occurred in plants infected via axillary buds on rhizome nodes. Healthy primary crowns of plants with infected axillary crown buds from which smutted rhizomes had grown remained unsmutted, indicative of mycelium growth in the direction of developing axillary crown buds; i.e., primary crowns were not infected via axillary crown buds. The perennial characteristic of the stripe smut pathogen was a function of mycelial colonization of crowns.