Early Blight of Potato: Causes, Symptoms, and Management Strategies
Disease Overview :
- Disease Name: Early Blight of Potato
- Causal Organism: Alternaria solani (fungus)
- Affecting Stage: Can affect plants at any stage, but symptoms are more severe on older leaves during the vegetative to tuber formation stages.
Symptoms :
Leaf Symptoms:
Small, dark brown to black spots on older leaves, forming concentric rings (target-like appearance), surrounded by yellow halos.
Stem Symptoms:
Dark brown to black lesions on stems and petioles, causing partial wilting.
Tuber Symptoms:
Sunken, irregularly shaped brown to black lesions on the surface, with dry, dark brown corky rot extending into the tuber flesh.
Favorable Conditions :
- Warm and Humid Weather: Temperatures between 20-30°C.
- Leaf Wetness: Periods of leaf wetness from dew, rainfall, or irrigation.
- Plant Stress: Plants stressed by nutrient deficiency, water stress, or excessive nitrogen application.
- Poor Airflow: Dense planting, reducing air circulation.
Management Strategies :
1. Cultural Control:
Use resistant varieties, rotate crops, plant certified disease-free seed potatoes, maintain proper plant spacing, avoid over watering, and remove crop debris.
2. Organic Control:
Spray neem oil or garlic-based biopesticides, apply Trichoderma harzianum, and use compost tea.
3. Chemical Control:
Apply Mancozeb, Chlorothalonil, Azoxystrobin, Cymoxanil + Mancozeb, and Difenoconazole.
Trade Names of Chemicals :
1. Dithane M-45: Mancozeb 75% WP (Indofil)
2. Kavach: Chlorothalonil 75% WP (Indofil)
3. Amistar: Azoxystrobin 23% SC (Syngenta)
4. Curzate: Cymoxanil 8% + Mancozeb 64% WP (DuPont)
5. Score: Difenoconazole 25% EC (Syngenta)
Effective Management :
By adopting these control measures, False Smut can be effectively managed, protecting rice crops from yield and quality losses.
