Identification symptoms

Infection on tubers

Severe infection

Target spot on leaf

1. This is a common disease of potato occurring on the foliage at any stage of the growth and causes characteristic leaf spots and blight.

2. Normally the disease symptoms become apparent during tuber bulking stage and develop leading to the harvest.

3. The early blight is first observed on the plants as small, black lesions mostly on the older foliage.

4. Spots enlarge, and by the time they are one-fourth inch in diameter or larger, concentric rings in a bull's eye pattern can be seen in the center of the diseased area.

5. Tissue surrounding the spots may turn yellow. If high temperature and humidity occur at this time, much of the foliage is killed.

6. Lesions on the stems are similar to those on leaves, sometimes girdling the plant if they occur near the soil line.