Japanese rose rust - Phragmidium rosae-rugosae

This rust attacks species of Rosa native to Asia. None of these host species are related to species of common ornamental roses, thus this rust species does not appear to be a threat to the North American rose industry.

Phragmidium rosae-rugosae Kasai 1910

Aecia forming a large dense cushion on petioles, stems or fruits, and lower surface of leaves often causing conspicuous deformation, pulvinate, more or less pulverulent, bright orange-yellow; aeciospores subglobose, broadly ellipsoid or somewhat angular, 20-28 × 16-22 µm, minutely verrucose, 1.8-3 µm thick, hyaline, walls orange yellow; paraphyses numerous, clavate, 50-85 × 14-20 µm, walls smooth, uniformly thin, nearly hyaline.

Uredinia hypophyllous, scattered or in groups, minute, round, 0.2-2 mm, pale yellow, pulverulent; urediniospores globose, subglobose, obovate, or broadly ellipsoid, 18-25 × 15-24 µm, walls 1.5-3 µm thick, hyaline, finely verrucose, germ pores obscure, numerous, scattered; paraphyses clavate, 54-150 × 9-20 µm, erect or incurved, wall 1.5 µm; hyaline, sometimes slightly thicker at apex, up to 3.5 µm.

Telia hypophyllous, scattered or gregarious, round or subround, 0.4-1 mm diam., pulverulent, reddish brown; teliospores cylindrical, 3-10-, mostly 5-7-celled, 60-138 × 32-47 µm, rounded at apex, walls 4-7 µm, yellowish brown, coarsely verrucose with subhyaline tubercles, apical papilla obscure, up to 5 µm long, with 3 germ pores in each cell, pedicels hyaline, persistent, 45-168 µm long.

See Hiratsuka et al. (1992) and Wei (1988) for more detailed descriptions.

Host range: Species of Rosa subfamily Rosoidea tribe Roseae, specifically Rosa pimpinellifolia, R. rugosa (Japanese rose), R. sericea, R. sericea subsp. omeiensis, and R. pimpinellifolia.

Geographic distribution: Asia (China, Japan, Korea)

This species is one of the numerous rust fungi on Rosa in Asia that can be distinguished using the key in Wei (1988).

References:

Wahyuno, D., Kakishima, M., and Ono, Y. 2001. Morphological analyses of urediniospores and teliospores in seven Phragmidium species parasitic on ornamental roses. Mycoscience 42: 519-533.

Wei, S.X. 1988. A taxonomic study of the genus Phragmidium of China. Mycosystema 1: 179-210.

Zhuang, J.-Y., and Wei, S.-X. 1994. An annotated checklist of rust fungi from the Mt. Qomolangma region (Tibetan Everest Himalaya). Mycosystema 7: 37-87.

Nomenclature

Specimens in BPI

Additional distribution data

Suggested citation: Yun, H.Y. Systematic Mycology and Microbiology Laboratory, ARS, USDA. . Invasive Fungi. Japanese rose rust - Phragmidium rosae-rugosae. Retrieved November 21, 2009, from http://nt.ars-grin.gov/sbmlweb/fungi/index.cfm .