Alternaria Leaf Blight (Cucurbits)

Description: Appears in midseason on the oldest leaves and spreads to younger leaves. Enlarging, circular brown spots with rings form on the upper leaf surface and are later covered by black, moldy growth. Defoliation may result in sunscalding of fruit. The fungus is seed-borne and overwinters in crop refuse and weeds.

Solution: If possible, don't plant where other cucurbits have been grown for the last two years, at least. Avoid overhead watering. Regular application of Soap-Shield^® Fungicidal Soap will reduce infection and slow its spread.