Arctic Rubus rust - Phragmidium arcticum

The rust fungus appears to be restricted to a few species of Rubus that occur in the northern latitudes and are not related to the economically important species.

Phragmidium arcticum Lagerh. ex Liro 1908

Spermogonia not found, probably lacking.

Aecia hypophyllous (on lower surface of leaves) or epiphyllous, caeomoid, yellow when fresh, incurved paraphysis few to many, to 60 µm long, 8-15 µm wide; wall 1.5-1.0 µm thick below, increasing on convex side and at apex to 1.3-5 µm. Aeciospores 16-26.5 × 14-21.5 µm; wall ca. 0.5-0.8 µm excluding warts, hyaline; warts flat-topped, irregular, labyrinthiform-tessellate, 0.5-1.0 µm high, 0.6-3.0 µm wide and 0.8-7 µm long; germ pores invisible but locations occasionally indicated by hemispherical refringent internal pore caps ca. 3.5-4.5 µm wide, scattered, probably 5-6.

Uredinia scarce, hypophyllous. Urediniospores 16-23.5 × 12.5-16.5 µm; wall ca. 0.6-1.0 µm, hyaline, echinulations ca. 0.6-0.8 µm high, 0.5-0.7 µm wide, at 1.0-2.0 µm spacing; internal refringent caps indicate pores ca. 5-6 scattered.

Telia hypophyllous. Teliospores 5-10 celled, 65-155 × 22-31.2 µm, including apiculus, nearly cylindric; wall 2.2-4 µm excluding warts, bilaminate, chestnut next to lumen and yellow on outside; yellow warts irregular. 0.5-2.5 µm high, 0.8-4.5 µm wide, occasionally to 9.0 µm long; germ pores 2-4 per cell, approximately equatorial; pedicels 50-154 µm long, swelling moderately in basal 1/3 to ½ with dextrosely helical striae crossing axis at 40-60°.

See Savile (1975) for a more detailed description.

Host range: Rubus subgenus Cylactis, specifically Rubus amabilis, R. arcticus (Arctic bramble), R. arcticus subsp. acaulia, R. caesius (European dewberry)

Geographic distribution: Asia (China, Japan); Europe (Estonia, Finland, Norway, Russia, Sweden); North America: Canada (Alberta, Quebec)

Notes: This fungus is morphologically similar to the widely distributed P. occidentale Arthur that occurs primarily on R. parviflorus (thimbleberry) (Savile, 1975).

References:

Cummins, G.B. 1962. Supplement to Arthur's Manual of Rusts in the United States and Canada. Hafner Publishing Company : 24.

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

Karatygin, I.V., and Asbukina, Z.M. 1996. Rust fungi (order Uredinales) from Russian Arctic. Mikol. Fitopatol. 30(5-6): 24-36.

Liro, J.I. 1908. Uredineae Fennicae Finlands Rostsvampar. Finska Litteratursallskapets, 640 pages.

Parmelee, J.A. 1989. The rusts (Uredinales) of arctic Canada. Canad. J. Bot. 67: 3315-3365.

Savile, D.B.O. 1975. Phragmidium arcticum. Fungi Canadenses 79: 1-2.

Watson, A.J. 1971. Foreign bacterial and fungus diseases of food, forage, and fiber crops. U.S.D.A. Agricultural Research Service : 111.

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