First report of leaf spot caused by Periconia igniaria on yellow starthistle in Russia.
In the summer of 2006, several hundred diseased yellow starthistle (YST; Centaurea solstitialis) plants were found near Taman, Russia. Symptoms of the disease were yellow water-soaked leaf spots. The fungus isolated from the diseased leaves conformed to Periconia igniaria [Didymosphaeria igniaria]. Colonies of the fungus grew rapidly on potato glucose nutrition medium with aerial mycelium from fluffy to pressed and colourless at the beginning and darkening to black with age. Upon conducting pathogenicity tests, inoculated plants exhibited typical symptoms of the disease, and Periconia igniaria was reisolated. No symptoms developed on the uninoculated plants. This is thought to be the first report of Periconia igniaria causing disease on YST.