Alternaria leaf blight

Alternaria leaf blight (Alternaria cucumerina) is a fungal pathogen of Cucurbits. The pathogens can persist in the soil for many years. The disease can move from field to field in soil on farm machinery, infected crop debris, and irrigation water. High soil temperatures favor disease development.

Symtpoms
Plants may be affected at any stage of growth. Young seedlings are killed or severely stunted. Older plants begin to wilt at midday for a few days, then permanently wilt and die. Vascular bundles are discolored becoming yellow or brown.

Prevention
Use resistant varieties when available. Avoid known infested fields for production of a susceptible crop. Wash equipment when moving from one field to another. Flooding fields for rice production reduces pathogen survival in the soil.