Small, circular spots develop on the foliage. Fungicides not required. Sanitation will help reduce foliage infection. Light green or yellow, irregular rings occur in leaves.
Plants tend to be smaller and low in vigor.
Destroy diseased plants. Propagate from healthy plants. Foliage becomes light green and finally a greenish yellow. The veins tend to remain green. Foliar applications of iron sulfate or copperas are usually effective if several applications are made when leaves are forming.