Sweet potato rust - Endophyllum kaernbachii

This fungus is a common rust in Indonesia (Boedijn, 1959) and other Asian countries that attacks members of the Convolvulaceae especially species of Ipomoea and Merremia (morning glory) among others. The hosts include economically important plants such as I. aquatica that is a noxious weed as well as a human and animal food source.

Endophyllum kaernbachii (Henn.) F. Stevens & Mendiola 1931

Spermogonia often lacking, if present, epiphyllous (on upper side of leaf), punctiform, not seen to open, orange yellow to brown.

Telia hypophyllous (on lower side of leaf), sometimes on amphigenous, pale yellow spots develop above and below leaves, 2-3 mm diam, leaf blade swollen from 150-375 µm in the region of the telia with peridia, slightly elevated forming densely clustered, yellow to brown orbicular spots, 2-10 mm diam, resembling the aecidial state, cupulate, 200-270 µm diam, with shitish, lacerate margins. Teliospores globose to broadly ellipsoid, slightly angular, 15-20 × 13-17 µm, walls hyaline, finely verrucose, 1 µm thick. Peridial cells rhomboid to rectangular, 18-28 × 14-22 µm, inner walls verrucose, 3-4 µm thick, outer walls finely striate, 6-8 µm thick.

See Hirastuka et al.,1992 and Stevens and Mendiola, 1931 for a more detailed description.

Host range: On related members of the Convolvulaceae including Hewittia sublobata as well as many species of Ipomoea and Merremia.

Geographic distribution: Widespread throughout Asia with a few reports from Africa (Tanzania, Sudan).

Notes: This fungus has an endocyclic life cycle with only a spermogonial, telial stage. After Stevens & Mendiola (1931) reported the telial stage, Cummins (1940) retained the name Aecidium kaernbachii for Endophyllum kaernbachii. The stage regarded as the aecial stage by early scientists is now known to be the telial stage. The protologue includes a description of the teleomorphic stage.

References:

Anonymous 1979. List of plant diseases in Taiwan. Pl. Protect. Soc., Republ. of China, 404 pages.

Arthur, J.C., and Cummins, G.B. 1936. Philippine rusts in the Clemens collection 1923-1926, II. Philipp. J. Sci. 61: 463-488.

Boedijn, K.B. 1959. The Uredinales of Indonesia. Nova Hedwigia 1: 463-496.

Cummins, G.B. 1940. Uredinales of New Guinea. Mycologia 32: 359-375.

Ebbels, D.L., and Allen, D.J. 1979. A supplementary and annotated list of plant diseases, pathogens and associated fungi in Tanzania. Phytopathol. Pap. 22: 1-89.

Lohsomboon, P., Manoch, L., Visarathanonth, N., Kakishima, M., Ono, Y., and Sato, S. 1986. Materials for the rust flora in Thailand II. Trans. Mycol. Soc. Japan 27: 271-281.

Mouchacca, J., and Horak, E. 1998. Annotated checklist of New Caledonian Basidiomycota. II. Rusts and Smuts. Mycotaxon 69: 13-30.

Stevens, F.L., and Mendiola, V.B. 1931. Aecioid short cycle rusts of the Philippine Islands. Philipp. Agric. 20: 3-17.

Tarr, S.A.J. 1963. A supplementary list of Sudan fungi and plant diseases. Mycol. Pap. 85: 1-31.

Nomenclature

Specimens in BPI

Additional distribution data

Suggested citation: Yun, H.Y. Systematic Mycology and Microbiology Laboratory, ARS, USDA. . Invasive Fungi. Sweet potato rust - Endophyllum kaernbachii . Retrieved November 21, 2009, from http://nt.ars-grin.gov/sbmlweb/fungi/index.cfm .