Oidium-type conidia

Oidium-type conidia are anamorphic (asexual) spores produced by members of the ascomycete order Erysiphales. Members of this order are plant pathogens known as powdery mildews and produce abundant dry powdery conidia on the surface of infected leaves. These conidia are responsible for the rapid spread of infection during the growing season.

The single-celled conidia are formed in chains; they are cylindrical or barrel-shaped, colorless and thin-walled. The conidia are large ranging from 20-40 µm in length.