Rust of Rubus saxitilis-Phragmidium acuminatum

Although relatively common in Europe and also found in Asia, this rust does not appear to have a broad host range on Rubus spp. and thus is not a threat to the berry industry in the United States.

Phragmidium acuminatum (Fr.) Cooke 1871

Aecia amphigenous, generally hypophyllous, scattered or grouped, rounded, minute, 0.3-0.5 mm diam. Elongated on veins, up to 5 mm long, yellow, surrounded by numerous hyaline, cylindrical paraphyses, rounded at apex, 50-75 µm long, 5-8 µm thick; aeciospores globoid to ellipsoid, sparsely aculeate, yellow 18-28 × 16-22 µm, wall 2-3 µm thick, with 3-7 pores.

Uredinia hypophyllous (on lower surface of leaves), scattered, obicular, 0.5-2 mm diam, pulverulent, orange; urediniospores subglobose or obovate, 18-28 × 15-20 µm, finely echinulate, 1-2 µm thick, 5-6 pores, scattered.

Telia hypophyllous, scattered or in groups, 1-3 mm diam, pulvinate, black. Teliospores cylindric or fusiform, 4-7 celled, 52-110 × 25-32 µm, wall 3-4 µm, densely verrucose, chestnut-brown, each cell with 3-4 pores, pedicels persistent, hyaline, up to 160 µm long, wider at base.

See Cunningham (1931) and Wilson and Henderson (1966) for a more detailed description.

Host range: Aecial, uredinial and telial stage: Rubus saxatilis L., Rubus sp.

Geographic distribution: Asia (China, Mongolia, Turkey), Europe (Austria, Bulgaria, Denmark, Finland, Germany, Latvia, Norway, Poland, Romania, Russia, Scotland, Sweden, United Kingdom)

A number of species of Phragmidium attack Rubus, although many of these occur only in Asia. Among those that exist primarily outside of North America but in Europe are included: P. acuminatum, P. arcticum, and P. bulbosum. Phragmidium arcticum occurs only at northern latitudes including in northern Canada. Phragmidium acuminatum and P. bulbosum can be distinguished by finely echinulate urediniospores of P. acuminatum versus the coarsely echinulate urediniospores of P. bulbosum. One of the other species of Phragmidium on Rubus in Europe, P. rubi-idaei, is widespread in North America. Phragmidium violaceum known primarily from Europe, Africa, and introduced into Australia as a biocontrol agent, was recently discovered in western North America.

References:

Braun, U. 1982. Die Rostpilze (Uredinales) der Deutschen Demokratischen Republik. Feddes Repert. Beih. 93: 213-334.

Cooke, M.C. 1871. Handbook of British Fungi, with Descriptions of All the Spices. Macmillan and Co., Ltd., London, -- pages.

Hylander, N., Jorstad, I., and Nannfeldt, J.A. 1953. Enumerato Uredinearum Scandinavicarum. Opera Bot. 1: 1-102.

Majewski, T. 1971. [Parasitic fungi of the Bialowieza National Park against the background of the mycoflora of Poland (Peronosporales, Erysiphaceae, Uredinales, Ustilaginales).]. Acta Mycol. 7: 299-398.

Petrak, F. 1962. Mykologische Beitrage zur osterreichischen Flora. Sydowia 16: 155-198.

Ryzhkin, D.V., and Levkina, L.M. 2004. Rust fungi of the North-East of Republic Mordovia. Mikol. Fitopatol. 38: 45-50.

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

Nomenclature

Specimens in BPI

Additional distribution data

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