Japanese Chamaecyparis-Malus/Sorbus Rust - Gymnosporangium miyabei

Gymnosporangium miyabei is apparently restricted to Japan where it is an important pathogen on Chamaecyparis pisifera or sawara cypress in the mountainous regions. The aecial stage occurs on Malus toringo and three species of Sorbus. This fungus occurs in natural and managed forests as well as in gardens.

Gymnosporangium miyabei G. Yamada & Miyabei

Aecia on leaves of Malus and Sorbus, hypophyllous, borne on frustum-like protuberances, roestelioid, 2-4 mm high; peridia retaining cornuted form, dehiscent at apex, not becoming lacerate, peridial cells rhomboid, 55-120 µm long, outer walls 3-6 µm, smooth, inner walls 8-20 µm wide, densely verrucose; aeciospores globose, large verrucose,18-30 µm in diam, walls cinnamon-brown, 1-1.5 µm.

Telia on stems of Chamaecyparis, caulicolous, on fusiform or irregular swellings with rough surface; pulvinate, applanate, or somewhat wart-like; teliospores chiefly 2-celled, sometimes with 1- or 3-celled, narrowly ellipsoid, 10-22 × 40-80 µm, walls 1-2.2 µm, brownish; pores usually one in each cell apical, sometimes near septum in upper cell and near pedicel in lower cell.

For a more detailed description see Hirastuka et al. (1992), Kern, (1973) and Lee and Kakishima (1999a, 1999b).

Host Range: Aecial stage known on Malus toringo, Sorbus alnifolia, S. commixta and S. japonica; telial stage on Chamaecyparis pisifera.

Geographic distribution: Apparently restricted to Japan. Although it was reported once from Korea (Hiratsuka 1940), this species was not found again despite extensive field work and a search of herbaria (Yun et al. 2009)

This fungus was initially named Roestelia solitaria on Sorbus alnifolia without a description (Miyabe, 1903). Dietel (1903) described the aecial stage but that name applies only to the asexual stage. The correct name, Gymnosporangium miyabei, was provided by Yamadae and Miyake (1908) who included a full description of the telial and aecial stages.

References:

Hama, T. 1987. [Studies on the important rust diseases of some conifers in the central mountainous region of Japan.]. Bull. Forest. Forest Prod. Res. Inst. (Japan) 343: 1-118.

Hiratsuka, N. 1936. Gymnosporangium of Japan. IV. Bot. Mag. 50: 661-668.

Hiratsuka, N. 1940. Uredinales collected in Korea IV. Bot. Mag. (Tokyo) 54: 433-437.

Kern, F.D. 1911. A Biologic and Taxonomic Study of the Genus Gymnosporangium. Bull. New York Bot. Gard. 7: --.

Kern, F.D. 1973. A Revised Taxonomic Account of Gymnosporangium. Pennsylvania State University Press, University Park, 134 pages.

Lee, S.K., and Kakishima, M. 1999. Surface structures of peridial cells of Gymnosporangium and Roestelia (Uredinales). Mycoscience 40: 121-131.

Lee, S.K., and Kakishima, M. 1999. Aeciospore surface structures of Gymnosporangium and Roestelia (Uredinales). Mycoscience 40: 109-120.

Yun, H.Y., Lee, S.K., Lee, K.J., and Kim, K.H. 2003. Two newly identified Gymnosporangium species, G. japonicum and G. cornutum, in Korea. Pl. Pathol. J. 19: 274-279.

Nomenclature

Specimens in BPI

Additional distribution data

Suggested citation: Yun, H.Y. Systematic Mycology and Microbiology Laboratory, ARS, USDA. . Invasive Fungi. Japanese Chamaecyparis-Malus/Sorbus Rust - Gymnosporangium miyabei. Retrieved November 21, 2009, from http://nt.ars-grin.gov/sbmlweb/fungi/index.cfm .