Although it is called Early Blight, it can occur at any point in the year if the conditions are met. It is a fungal disease that affects many members of the potato family and can severely damage the crops. It is one of the blights that was responsible for the Irish potato famine from 1845-1849.
Small brown spots on the older leaves with concentric rings eventually spread out over the leaf. Ultimately, leaves turn yellow and die. Later the stems and fruits will show these symptoms and cause the death of the plant.
Poorly nourished plants in warm and humid conditions.
Older leaves showing brown spots with concentric rings.
Yellowing of leaves.
Wilting and death of top growth.
Application of a bio-fungicide repeated at weekly intervals as needed.
Application of a Copper fungicide (or available equivalent) to help reduce the damage of the fungus.
Having good air circulation around plants. Good plant and tool hygiene. Clearing dead material from around plants. Good soil nutrients.