FIRST REPORT OF PUCCINIA IRIDIS ON IRIS CROATICA IN CROATIA

During summers of 2007 and 2008, in the Nature park Zumberak-Samoborsko gorje and the Botanical Garden of the University of Zagreb leaf spots with evident rust pustules were observed on the leaves of Croatian iris (Iris croatica Horvat et Horvat), an endemic and protected plant species. Uredinia were amphigenous, brown-orange, while telia were black and hypophyllous. Based on the morphological characteristics of urediniospores and teliospores, as seen under the light microscope, the fungus was identified as Puccinia iridis (DC) Wallr. (Gaumann, 1959). Urediniospores were yellow-brown, echinulate, sphaerical to ovoid 28-35x20-25 pm in size. Teliospores were bicellulate, golden-brown, clavate, cylindric, 35-50x14-20 mu m in size, with pedicels 20-30 mu m long. P. iridis is heteroecious with aerial stage developing on species of the genera Urtica and Valeriana, whilst uredinia and telia appear mostly on taxa of the genus Iris, but also on some species of the family Iridaceae (e.g. Dietes, Crocus, Belamcanda). To date, P. iridis, a new record from Croatia, has been reported from 69 Iris taxa (Farr and Rossman, 2009), but not from Iris croatica which, therefore, is also a new host for this rust. Plant material with uredinia and telia of P. iridis is stored, as a herbarium specimen, in the Department of Plant Pathology at the Faculty of Agriculture of Zagreb.