Anamorph of a powdery mildew was collected from Convolvulus arvensis (Convolvulaceae) in 2021 in Korea. Based on the morphological examination and molecular phylogenetic analyses of the internal transcribed spacer and large subunit rDNA gene, the powdery mildew was identified as Erysiphe convolvuli. This powdery mildew species is commonly found in Europe and North America, but rarely in East Asia. The holomorph of this powdery mildew was first recorded on Calystegia hederacea in Korea. Conclusively, this is the first report of E. convolvuli on C. arvensis and the second record of this powdery mildew species in Korea.