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.