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 equipment.
Solution: Avoid 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 as taken hold, sprays are generally ineffective.