First report of smut of Viola caused by Urocystis violae in Iran.

A specimen of Viola sp. with smut symptoms was collected and studied from Arasbaran protected region. Preliminary study revealed that the fungus is a member of the genus Urocystis Rabenh. ex Fuckel. The specimen characterized by sori usually in the petioles as fusiform loculate swellings up to several cm long which distort the attacked parts. Sori infrequently on leaf veins as blister like swellings. Sourus covering of host tissue persistent, eventually rupturing irregularly to expose the spore mass. Spore mass powdery, blackish-brown, composed of spore balls. Spore balls globose, ovoid to elongated, irregular 21-73 x 21-45 µm, reddish-brown, each composed of 2-15 (-18) spores, completely covered by sterile cells. Spores globose, ovoid, elongate or irregular, 11-18 x 9-13 µm, yellowish- to reddish-brown, smooth. Sterile cells variable in shape and size, 6-12 µm diameter, smooth (Fig 1). Above characteristics of the studied fungus fit with description of Urocystis violae (Sowerby) E. Fisch. (VANKY, K. 1994. European Smut Fungi). Based on literature records (ERSHAD, D. 2001. Smut Fungi Reported From Iran) U. violae is a new species for the Iranian mycobiota. Urocystis kmetiana Magnus, the only recorded smut fungus on Viola in Iran differs from above species due to the sori which are usually in the flowers, specially the ovaries, not the vegetative parts of the host. A voucher specimen was preserved in the fungus reference collection of the Ministry of Jihad-e –Agriculture (IRAN) at the Iranian Research Institute of Plant Protection, Tehran. Sever attacks of this smut species on cultivated violets specially, on nursery plants have been reported in other countries (MORDUE, J.E.M. 1988. Mycopathologia 103: 184).