Raspberry rust - Phragmidium rubi-thunbergii

Some hosts of this rust are species of Rubus that are considered economically important for the berry industry in North America. Although it is restricted to Asia at present, this rust may be a threat to North American agriculture.

Phragmidium rubi-thunbergii Kusano 1904

Uredinia hypophyllous, scattered or in small groups, minute, round, 0.3-0.7 mm diam, yellow, pulverulent; paraphyses clavate, erect or incurved, wall uniformly thin, hyaline; urediniospores globose, subglobose, obovate, broadly ellipsoid or obovoid, 16-26 × 12-20 µm; walls 0.8-1.8 µm thick, coarsely echinulate, pale yellow.

Telia hypophyllous, scattered or gregarious, minute, round or irregular, 0.1-0.3 mm diam, pulverulent, black; teliospores cylindrical, 4-5- (mostly 4-) celled, 40-74 × 22-28 µm (49-85 × 21-35 µm fide Hiratsuka et al., 1992), rounded at apex, more or less constricted at septum, walls 2.2-2.6 µm, brown, smooth, 2-3 germ pores in each cell; pedicels hyaline, persistent, 65 µm long.

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

Host range: Species in Rubus subgenus Idaeobatus, specifically R. hirsutus, R. idaeus (raspberry), R. nishimuranus, R. niveus (hill raspberry), R. parvifolius (thimbleberry), and R. pileatus

Geographic distribution: Asia (China, Japan)

This fungus is similar to Phragmidium formosanum in teliospores but P. rubi-thunbergii has more rounded urediniospores (Hiratsuka et al., 1980). Wei (1988) provides a key to the numerous species of Phragmidium that are known to occur on Rubus in Asia.

References:

Hiratsuka, N., Kaneko, S., and Nishigaki, H. 1980. A taxonomic revision of the species of Phragmidium in the Japanese Archipelago. Contributions to the rust-flora of eastern Asia XIV. Rep. Tottori Mycol. Inst. 18: 53-88.

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

Zhang, N., Zhuang, J.-Y., and Wei, S.-X. 1997. Fungal flora of the Daba Mountains: Uredinales. Mycotaxon 61: 49-79.

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. Raspberry rust - Phragmidium rubi-thunbergii. Retrieved November 21, 2009, from http://nt.ars-grin.gov/sbmlweb/fungi/index.cfm .