Late blight(Phytophthora infestans)

Symptoms

• All the aerial parts are affected.
• Small green patches appear on the upper surface of leaves on the margins.
• Lesions are light green, later they turn brown, purplish brown and then black.
• During wet and humid conditions, white mildew growth is seen on the upper surface of leaves.
• The lesions expand and coalesce and spread to adjacent leaves.
• The necrotic central portion of leaf dry off, fall from the lesion, causing shot holes

Management

• Use of disease-free seeds
• Burn all the infected debris
• Crop rotation

Chemical Control