Yamada Rubusrust - Phragmidium yamadanum

Most hosts of this rust are species of Rubus native to Asia, thus this pathogen is not considered a threat to North American agriculture.

Phragmidium yamadanum Hirats. 1935

Uredinia hypophyllous, scattered or in small groups, minute, round, yellow, pulverulent, 0.1-0.5 mm; paraphyses clavate, 45-65 × 12-20 µm, wall 1-1.5 µm; hyaline; not or slightly thickened at apex; urediniospores globose, subglobose, obovate, or ellipsoid, 18-34 × 11-22 µm; walls 1.2-1.8 µm thick, minutely echinulate, germ pores obscure.

Telia hypophyllous, scattered or gregarious, minute, round or irregular, 0.4 mm diam, pulverulent, blackish brown or black; teliospores cylindrical, 4-9-, mostly 7-8-celled, 60-135 × 22-30 µm, rounded at apex, not constricted at septae, walls 2.5-3.5 µm, chocolate brown, minutely and closely verrucose with subhyaline tubercles, 3 germ pores in each cell, pedicels hyaline, persistent, 180 µm long, swelling abruptly to broadly clavate or subglobose in the lower part.

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

Host range: Rubus subgenus Idaeobatus, specifically R. idaeopsis, R. ikenoensis, and R. pungens as well as reports on Rubus spp.

Geographic distribution: Asia (China, Japan)

Notes: Phragmidium yamadanum is distinguished from other species of Phragmidium on Rubus in Asia by the verrucose teliospores with pedicels that are hygroscopic becoming broadly clavate to subglobose (Wei 1988).

References:

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, W.-Y., Ed. 2005. Fungi of northwestern China. Mycotaxon, Ltd., Ithaca, NY, 430 pages.

Nomenclature

Specimens in BPI

Additional distribution data

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