Disease spread in the field requires free water and occurs by rain splash or overhead irrigation carrying bacteria from infected to healthy plants. Transfer is aided by insects, plant contact, wind, and hands or clothing of pickers. Temperatures of 75-82 degrees Fahrenheit, high humidity, and excessive nitrogen fertilization favor disease development. Control Cucumbers should be grown from clean seed in an area isolated from other cucurbit fields and on land that has been free of cucurbits for one or two years. Clean seed is produced in dry inland areas of California.
Copper containing sprays can help control the disease.
Copper fungicides such as Kocide 101, Kocide 606, Champion, or Champion Flowable can be used by commercial growers. Homeowners can use Bordeaux Mixture. These fungicides should be applied in strict accordance with label instructions. Current recommendations are available at county extension offices. Copper sprays should not be continued in dry weather, especially hot, dry weather, because the sprays may cause plant injury.