Class Plectomycetes
Order Erysiphales
Fungi of order erysiphales appear as white powdery coating on the surface of host hence they are popularly known as powdery mildews . Mature cleistothecia of erysiphales are characterised by the presence of appendages .
They are biotrophic parasites ( derive their nutrients from living host cells ) of flowering plants causing the powdery mildews disease . Fruiting bodies are cleistothecium which bears myceloid appendages in erysiphe , circinoid appendages in uncinula . They have conidia in basipetal succession .Uncinula causes powdery mildew of grape - vines . Sphaerotheca fuliginea causes powdery mildew of cucurbits .
Erysiphae
Sub division - Ascomycotina
Class - Plectomycetes
Order - erysiphales
Family - erysiphaceae
Genus - Erysiphe
Mycelium is superficial ( ectoparasite ) , branched and septate . Erysiphe shows branched haustoria . Digitate haustoria is found in erysiphe graminis . Sex organs usually develop in late summer and conidia develop in cool and humid conditions .