Podosphaera xanthii (powdery mildew of cucurbits)

Taxonomy

Domain	Eukarya
Kingdom	Fungi
Phylum	Ascomycota
Subphylum	Pezizomycotina
Class	Leotiomycetes
Subclass	Leotiomycetidae
Order	Helotiales
Family	Erysiphaceae
Genus	Podosphaera

Scientific Name

Podosphaera xanthii

Common Name

powdery mildew

Overview

Powdery mildew, caused by the fungus Podosphaeria xanthii, is much more widespread on cucurbits than downy mildew, especially during dry hot periods.

Symptoms and Signs

This disease is characterized by a white or brownish, mealy growth found on the upper and lower sides of the leaves and young stems. If plants are severely attacked, the leaves and young stems may wither and die. In less severe cases, the plant may be weakened or stunted. Early defoliation resulting from the disease may cause premature ripening or sun scald.

Management

The use of preventive fungicide applications is the most effective means of suppressing powdery mildew. However, some varieties may demonstrate tolerance to this disease. Fungicides used in conjunction with tolerant varieties offers the most complete disease management program for powdery mildew on cucurbits.