The first black mildew fungus associated with Apiaceae is collected from the state of Minas Gerais, Brazil. The new species is described, illustrated, and compared morphologically with species reported on hosts belonging to the related Araliaceae. Additionally, two efficient methods for extracting DNA from biotrophic fungi are described. Phylogenetic 28S rDNA sequence analyses confirm Meliolales as a distinct order within Sordariomycetes.