From blight to bright: Tips for a blight-free potato season.

 

Early blight of potato-

DISEASE: Early blight

PATHOGEN: Alternaria solani

HOSTS: Tomato (Lycopersicon esculentum), Potato (Solanum tuberosum)

What is this disease?

Early blight is a common potato disease that's caused by a fungus called Alternaria solani. This fungus can also attack other related plants like tomatoes and some mustards. Early blight usually starts on older leaves first, and it thrives in warm, humid weather. Interestingly, it doesn't often affect young, healthy potato plants.

What are the symptoms ?

Leaves:

• Tiny dark, dry patches that grow into larger brown-black circles or ovals.
• Patches often have sharp edges where they meet veins.
• Rings of dead tissue inside the patches, making them look like targets.
• Yellow or greenish yellow rings around growing patches.
• Lower leaves turn yellow and die when patches get big.

Stems:

• Dark brown to black sunken spots that look like lenses.
• Light-colored centers and rings of dead tissue inside the spots.

Tubers:

• Dark, round to irregular patches with raised, purple or gray edges.
• Brown, dry, and leathery flesh under the patches.
• Flesh turning water-soaked and yellow as the disease spreads.
• Flesh turning water-soaked and yellow as the disease spreads.

                            

How to Prevent? 

Preventive Measures:

• Use certified, disease-free seeds: This avoids introducing the fungus right from the start.
• Rotate crops: Don't plant potatoes in the same field year after year to break the disease cycle.
• Practice good sanitation: Remove and destroy infected plant debris after harvest.
• Maintain proper spacing: Ensure good air circulation within the crop stand to reduce humidity.
• Monitor weather conditions: Be extra vigilant during warm, humid periods when the fungus flourishes.

Cultural Methods:

• Choose resistant varieties: Opt for potato varieties known for their resistance to early blight.
• Maintain proper irrigation: Avoid overwatering, but ensure plants receive adequate moisture.
• Hilling: Mound soil around the base of plants to protect developing tubers from infection.
• Mulching: Cover the soil around plants with organic mulch to suppress weed growth and maintain soil moisture.

Mechanical and Physical Methods:

• Handpicking: Remove and destroy infected leaves and stems early on to prevent further spread.
• Pruning: Trim off lower leaves, where infection usually starts, to improve air circulation.
• Intercropping: Plant taller crops around potatoes to provide shade and reduce humidity.

Biological Control:

• Biofungicides: Apply commercially available biofungicides containing beneficial bacteria or fungi that compete with the early blight fungus.
• Trichoderma harzianum: Introduce this beneficial fungus to the soil to suppress the growth of early blight pathogens.

Chemical Control:

• Fungicides: Use fungicides like chlorothalonil, mancozeb, or copper-based products as a last resort, following recommended rates and application schedules.

 

Remember:

• Combine multiple methods: Employing a combination of these strategies is the most effective way to manage early blight.
• Monitor continuously: Regularly inspect your potato crop for signs of infection and take action quickly if necessary.
• Consult local experts: Seek advice from our  agricultural expert  or specialists for specific recommendations based on your region and conditions.