In central Europe, including Germany, Telekia speciosa (heart-leaved oxeye) is a synanthropic, non-native plant species commonly grown as an ornamental plant. A powdery mildew has recently been introduced on this host in Germany. This powdery mildew has previously been assigned to Golovinomyces cichoracearum (≡ Erysiphe cichoracearum) sensu lato. Two German specimens of powdery mildew on Telekia have been sequenced and phylogenetically analysed. The analyses revealed that the German sequences obtained from the Telekia powdery mildew are identical with a sequence retrieved from Golovinomyces inulae on Pentanema salicinum (≡ Inula salicina) collected in Switzerland. Furthermore, holotype material of G. inulae, described from Korea, has been sequenced, which confirmed G. inulae as causative agent of the Telekia powdery mildew. The current distribution of G. inulae in Germany is briefly discussed including a first report of this pathogen from Austria.