The influence of mountain meadow management on the occurrence of Puccinia perplexans Plow.

In the autumn of 1999, a greater occurrence of uredinia of the rust Puccinia perplexans was noticed on the leaves of a grass species (Alopecurus pratensis) in permanent grass stands in the central Bohemian Forest (location Zhůři, altitude 10501080 m). Three methods of grassland management were tested at the experimental site: (1) Mowing once a year, (2) Mulching once a year and (3) No management (fallow stand). Disease severity was evaluated in three terms during September and October 1999. The most severely attacked by the rust was A. pratensis in the mown stand. A smaller infection occurred in the mulched stand, and the smallest extent of attack was found in the unmanaged stand. In 1999, a mass occurrence of the rusts at the ure- dinial and incipient telial stages was recorded on various grass species: Puccinia coronata var. coronata on A. pratensis and Holcus mollis, Puccinia festucae on Festuca rubra, Puccinia graminis subsp. graminicola on Deschampsia cespitosa, P. perplexans on A. pratensis, Puccinia poarum on Poa pratensis. In the subsequent year (2000), the same rust species were found on the same host plants except for P. perplexans. The occurrence of this species was mostly influenced by climatic conditions.