First Report of the Rust Fungus Coleosporium tussilaginis on Tussilago farfara in Turkey

Abstract

Tussilago farfara L. ("coltsfoot", Asteraceae) is indigenous to Eurasia, including Turkey, but has been classified as a Class A noxious weed in North America. Plant pathogens are being sought as potential candidates for biological control of coltsfoot. A rust fungus, Coleosporium tussilaginis (Pers) Lev. has been reported to cause disease on T. farfara from Europe, Russia, and Japan (2). During August of 2001 and 2002, rust pustules were observed on coltsfoot leaves in Kizilcahamam, Ankara, Turkey. Diseased plant specimens with rust pustules were collected, examined microscopically, and compared with published descriptions (1) and specimens in the U.S. National Fungus Collections in Beltsville, MD. The causal agent was subsequently identified as the fungus Coleosporium tussilaginis (Pers.) Lév. on the basis of symptomatology and morphology of uredinial and telial stages such as: clustered, golden-orange, sub-epidermal, erumpent, uredinia approximately 1.0 × 2.0 mm in diameter on the abaxial surface, and corresponding achlorotic areas on the adaxial leaf surfaces; thick-walled (3.0 to 4.0 μm), pale orange, coarsely verrucose, variously shaped (mostly broadly ellipsoid or angular) urediniospores measuring 23.5 to 33.0 × 20.0 to 25.7 μm (average = 27.3 × 23.3 μm), with obscure and scattered germ pores; and orange-red telia on the abaxial leaf surfaces covered by a gelatinous apical layer enclosing orange-red, cylindrical to clavate teliospores measuring 50.0 to 80.0 × 18.0 to 28.0 μm. A voucher specimen of this material has been deposited in the U.S. National Fungus Collections (BPI 863516). To the best of our knowledge, this is the first report of C. tussilaginis rust on coltsfoot in Turkey.