Phylogenetic connections among 20 teleomorphic genera of powdery mildew fungi are discussed. A new system of the order Erysiphales is proposed. The order is divided into three families (Blumeriaceae, Erysiphaceae and Leveillulaceae), four families (Erysiphoideae, Golovinomycetoideae, Leveilluloideae, and Phyllactinioideae) and several tribes. Section Golovinomyces U. Braun is raised to the rank
... [Show full abstract] of the genus.