First report of Melampsoridium hiratsukanum infecting alder (Alnus orientalis var. orientalis) in Turkey

During a disease survey between 1999 and 2001, in the Antalya province of southern Anatolia (Fig. 1), uredinial sori caused by a rust fungus were observed on the leaves and fruits of Alnus orientalis var. orientalis (Fagaceae).

The symptoms observed on infected leaves and the spore morphology matched with those described for a Melampsoridium species (Kurkela et al., 1998; Roll-Hansen & Roll-Hansen, 1981). The sori, which occurred on the lower side of the leaves, were 3-5 mm in diameter and orange-yellow in colour (Fig. 2). Microscopic examination revealed uniformly echinulate urediniospores, measuring 21-35 x 10-16µm. The thickness of the episporium was 1.1-1.45 µm and the ostiolar cells, 41.5-51.8 µm long. Two Melampsoridium species have been described on alders: M. alni and M. hiratsukanum. Melampsoridum alni is very similar morphologically to the leaf rust of birch, M. betulinum, whereas M. hiratsukanum, is morphologically distinguishable from the two (Szabo, 2002). The rust identified in this report accuratley matches the morphological description of M. hiratsukanum.

This is the first record of M. hiratsukanum on alder in Turkey. This fungus has been recorded on a diverse range of Alnus species in the world (Farr et al., 2004), however this is the first specific report of infection on Alnus orientalis var. orientalis.