Asian Phragmidium Rubus rust - Phragmidium arisanense

This rust occurs only on species of Rubus native to Asia that are not closely related to the economically important berries. Thus, this rust does not appear to be a threat to the North American berry industry.

Phragmidium arisanense Hirats. & Hashioka 1934

Uredinia hypophyllous (on lower surface of leaves), scattered or in small groups, round, minute, 0.2-0.8 mm diam, early exposed, somewhat pulverulent, orange-yellow; paraphyses numerous, cylindrical or clavate, 50-80 × 12-20 µm, somewhat incurved, walls thin (1 µm), smooth, colorless; urediniospores globose, subglobose, obovate or broadly ellipsoid, 18-28 × 14-22 µm, epispore minutely echinulate, colorless, 1.5 µm thick; contents orange-yellow.

Telia hypophyllous, scattered or aggregate, minute, round or irregular, 0.2-0.4 mm diam, early exposed, pulverulent, black; teliospores cylindrical, 5-7 celled, 59-98 × 27-35 µm, without apical papilla, rounded at both ends, not or slightly constricted at each septum, epispore smooth (verrucose in Wei, 1988), 2.5-4.0 µm thick, sometimes slightly thickened above up to 5 µm, with 3 germ pores in each cell, pericels hyaline, persistent, up to 103 µm long, hygroscopic.

See Wei (1988) for a more detailed description.

Host range: Primarily on species in Rubus subgenus Idaeobatus: Rubus arisanensis, R. flosculosus, R. mesogaeus, R. rarissimus, R. ritozanensis, R. xanthocarpus. These species of Rubus are native to Asia.

Geographic distribution: Asia (China, Japan, Taiwan)

This fungus is similar to P. nambuanum Dietal 1908. However, there are differences between these two species such as the number of teliospore cells, width of the teliospores and thickness of teliospore wall (Wei, 1988).

References:

Ito, S. 1950. Mycological Flora of Japan. Vol. II. Basidiomycetes. No. 3. Uredinales -- Pucciniaceae. Uredinales Imperfecti. Yokendo Ltd., Tokyo, 435 pages.

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

Zhuang, W.-Y., Ed. 2001. Higher Fungi of Tropical China. Mycotaxon, Ltd., Ithaca, NY, 485 pages.

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. Asian Phragmidium Rubus rust - Phragmidium arisanense. Retrieved November 21, 2009, from http://nt.ars-grin.gov/sbmlweb/fungi/index.cfm .