• It is present in both hills & plains.
• Brown-black necrotic spot-angular, oval shape characterized by concentric rings.
• Several spot coalesce & spread all over the leaf.
• Shot holes on fruits.

Identification of pathogen:

Mode of spread and survival:

• The conidia and the mycelium in the soil or in the debris of the affected plants can remain viable for more than 17 months.
• These conidia or the new conidia found on the overwintered mycelium bring about the primary infection of the succeeding potato crop.
• Secondary infection is more important in the spread of the disease.
• The conidia formed on the spots developed due to primary infection are disseminated by wind to long distances.
• The conidia from the affected plant may also be disseminated to the adjoining plants by rain and insects.

Epidemiology:

• Dry warm weather with intermittent rain.
• Poor vigor. Temperature: 25-30°C.
• Poorly manured crop.

• Disease free seed tubers should be used for planting.
• Removal and destruction of infected plant debris should be done because the spores lying in the soil are the primary source of infection.
• Very early spraying with Zineb or captan 0.2% and repeating it for every 15 – 20 days gives effective control.
• The variety Kufri Sindhuri possesses a fair degree of resistance.