Leaf Spot (Cucurbits)
Angular to irregular water-soaked spots form in the
leaves. When moist, droplets of bacteria ooze from the
underside of lesions and dry to a white residue. The
lesions later turn gray to brown, dry, and tear away,
leaving large irregular holes. The bacterium overwinters
in diseased plant refuse and on the seed coat. Disease
is spread by rain splash and on hands, clothing and
working around cucurbits when foliage is wet. Bacterium
survival in the soil can be reduced if you work soil
only when it is dry. Do not water with overhead sprinklers.
Spray with Soap-Shield® Fungicidal Soap
before the disease normally appears. Once an epidemic
has taken hold, sprays are generally ineffective.