Host: Hylotelephium (cultivated)
ID based on host association. Liu & Braun (2022) note that E. polygoni taken in the strict sense, when reported "on Hylotelephium spp. and Sedum sp. are likely Erysiphe sedi (Shin et al. 2019; Bradshaw et al. 2020a)"
iNaturalist observation

Reference
Liu, M. & Braun, U. 2022. Powdery mildews on crops and ornamentals in Canada: a summary of the phylogeny and taxonomy from 2000 – 2019, Canadian Journal of Plant
Pathology, 44:2, 191-218, DOI: 10.1080/07060661.2021.1986744