Understanding and Managing Late Blight In Potato

Late blight is one of the most destructive diseases affecting potato crops worldwide. Caused by the pathogen Phytophthora infestans, it can rapidly spread under favourable conditions, causing significant losses in potato yield to the extent of 30%-80%. 

In this blog we will explain what is late blight of potato, its symptoms, favourable environment conditions and explore effective control measures to manage late blight in potato crop, focusing on timely practices,and essential fungicide applications to help farmers protect their crops and improve yields.

What is late blight of potato

Late blight is a disease commonly found in solanaceous plants like potatoes and tomatoes. It is caused by Phytophthora infestans, an oomycete pathogen also known as a water mold. This pathogen infects potato plants at any growth stage, targeting the foliage and tubers. Early symptoms appear as small, circular spots on the leaves, ranging from light to dark green

Overview of Late Blight of Potato

Favourable factors for Late Blight of Potato

Late blight thrives in warm, humid weather, especially in areas with alkaline soils.

High disease incidence typically follows a Smith Period, defined as:

• Duration: Two consecutive days (ending at 9:00 a.m. each day)
• Conditions: Temperatures of at least 10°C with over 90% relative humidity for 11+ hours each day.

Hot, dry conditions can temporarily halt disease spread.

Symptoms of Late Blight in Potato

The initial signs of late blight include small, circular spots in shades of light to dark green, which typically appear on the lower side of the leaves and gradually spread to the leaf tips or edges.

Some common symptoms of late blight are as follows:

• Watery, blister-like spots in green or yellow form on the foliage.
• Brown or black lesions develop on the underside of leaves.
• Leaves begin to rot 1–4 days after infection; tan blisters form in dry conditions, while blue-grey mycelium appears in moist conditions.
• Tubers show two types of rot: dry rot and wet rot.
• Dry rot: Fungal damage penetrates 5–15 mm deep, with bluish-black to reddish-brown colouring.
• Wet rot: Deeper rot, extending 24–45 mm, infects the entire potato, with colonies that appear white and release water.

Measures to Control Late Blight in Potato

By using the right fungicides to fight late blight, farmers can protect their potato crops and increase their yield

Mode of Action of Katyayani Dismiss

Katyayani Dismiss (Dimethomorph 50% WP) works through systemic action by disrupting the formation of the fungal cell wall. This weakening of the cell ultimately leads to the death of the fungus, effectively controlling its spread and protecting the crop.

Key Benefits of Katyayani Dismiss (Dimethomorph 50% WP)

1. Provides exceptional control over Late Blight: This formulation is highly effective in managing these diseases, ensuring healthier crops and improved yields.
2. Effective against all stages of fungal development: Whether it's the early, mid, or late stages of infection, this product targets fungi at every point in their lifecycle, enhancing overall efficacy.
3. Unique mode of action: Induces cell wall lysis: By disrupting the integrity of the fungal cell wall, it effectively weakens and ultimately kills the fungus, preventing further spread and damage.
4. Translaminar movement for thorough protection: This ensures that the product penetrates the leaf surface, providing comprehensive coverage while also acting as an anti-sporulant to prevent new spore formation.

Conclusion

Late blight poses a severe risk to potato crops, but with timely action and with the use of right fungicides like Dimethomorph 50% WP (Katyayani Dismiss), farmers can effectively manage and reduce its impact. By recognizing symptoms early, monitoring weather conditions, and applying targeted treatments, farmers can protect their crops, boost yields, and ensure healthier potato production.

FAQs related to Late Blight of Potato

Q. What is late blight of potato?

A. Late blight is a severe disease caused by Phytophthora infestans, affecting all above-ground parts of potato plants.

Q. What are the symptoms of late blight?

A. Symptoms include circular leaf spots, watery blisters, brown lesions, rapid leaf rot, and tuber rot (dry and wet).

Q. Which fungicide is effective against late blight?

A. Katyayani Dismiss (Dimethomorph 50% WP) is recommended at 400-450 grams per acre for effective control.

Q. What conditions favour late blight of potato?

A. Late blight thrives in warm, humid weather, especially after two consecutive days of temperatures above 10°C and over 90% humidity.

Q. How can late blight be managed?

A. Timely fungicide applications, early symptom recognition, and monitoring weather conditions are essential for effective management of late blight.