Powdery mildew of cereals is caused by Ascomycetes.
The fungi responsible for powdery mildew belong to the order Erysiphales within the phylum Ascomycota.
Common examples that cause powdery mildew on cereals include species of Blumeria, such as Blumeria graminis, which is known to infect wheat, barley, and other grasses.
These fungi are characterized by their superficial growth on the plant surface, forming a white, powdery mass, and they produce asexual spores called conidia.