Wet and humid conditions from mid-summer and through the fall favor development of Cercospora leaf spot. Infected leaves from the previous year are the main source of inoculum. The infection starts from lower leaves and spreads rapidly by wind or rain splash
Cercospora leaf spot will cause tan to dark brown spots which will be randomly scattered on leaves
Severely affected leaves turn yellow with areas with large lesions.
The organism can be identified by the characteristic conidia.