Late Blight(Phytophthora infestans)

Symptoms

• The sickness harms leaves, stems, and tubers.
• It starts as small light green spots on leaves, which grow into big wet patches mainly from the tips or edges of leaves.
• A white mildew (fluffy growth) forms around the dead areas on the underside of leaves.
• Affected leaves look wrinkled as if they've been burned by hot water and eventually decay and dry up. When drying, leaves become brown or black.
• In dry weather, wet areas on leaves turn brown and dead.
• On stems, there are light brown stretched patches formed which might circle the stem. Infected stems start turning black from the tips and eventually dry out.
• Serious infections lead to all leaves rotting, drying out, and falling off, stems drying out, and plants dying.
• Tubers get reddish-brown, shallow to deep, dry rotten patches. The inside of the affected tuber turns 'caramelized' with a sugary feel.
• Often, a metallic sheen develops on the edges of the affected tissue.
• This disease works very fast. Without control, infected plants will die in two or three days.

Management

• Before storing, carefully inspect seed potatoes.
• Remove and deeply bury any tubers affected by blight.
• Build ridges high enough to cover all daughter tubers and lower their risk of getting infected.
• Clean up and get rid of any leftover plant debris and other plants that could host the disease in the field.
• If the weather conditions (temperature 10-20°C, humidity >80%) are good for the disease to spread, stop watering right away. If needed, only lightly water.
• When 75% of the crop's leaves are affected by the disease, cut and remove the stems from the field, burying them deeply. Wait 2-3 weeks after removing the stems before digging up the tubers.
• Choose varieties of potatoes that grow quickly.
• Plant potato varieties that are resistant to the disease, such as Kufri Naveen, Kufri Khasigaro, Kufri Jeevan, Kufri Alankar, Kufri Badshah, Kufri Muthu, Swarna, etc.
• Use fertilizers carefully.
• Avoid letting the soil get waterlogged.

Chemical Control

Extremely Toxic

Highly Toxic

Moderately Toxic

Slightly Toxic