1. Disease Name: Black Scurf of Potato

2. Causal Organism:

Rhizoctonia solani (fungus)

3. Affecting Stage:

• Affects the crop during the sprouting, vegetative, and tuberization stages.
• Primarily seen on tubers at harvest and during storage.

4. Symptoms:

Stem and Leaf Symptoms: 

• Poor emergence or irregular growth of plants due to damage to emerging sprouts.
• Dark brown lesions or cankers on the stem near the soil line, causing plant stunting.
• Severe infections may cause wilting, yellowing of lower leaves, and plant death.

 Tuber Symptoms: 

• Presence of black, hard, crust-like structures (sclerotia) on the tuber surface, giving it a rough appearance.
• Tuber infections may not penetrate deeply but can affect the marketability.
• In storage, infected tubers may develop dry rot or shriveling over time.

5. Favourable Conditions:

• Cool and moist soil conditions during sprouting and tuber formation.
•  
• Poor soil drainage or waterlogging.
• Use of disease infected seed tubers or planting in infested fields.
• Dense planting and poor crop rotation practices.

6. Cultural Control:

• Use certified, disease-free seed potatoes to prevent initial infections.
• Rotate crops with nonhost crops like cereals or legumes to break the disease cycle.
• Avoid planting in fields with a history of Rhizoctonia infection for 2-3 years.
• Practice proper soil drainage and avoid overwatering during the crop cycle.
• Ensure early planting in warmer soils to reduce disease severity.
• Harvest tubers at the right maturity to minimize sclerotia formation.

7. Organic Controls:

• Treat seed tubers with Trichoderma viride or Pseudomonas fluorescens to suppress the pathogen.
• Apply well decomposed organic manure or compost to improve soil health.
• Use neem cake or other biofertilizers as a soil amendment to reduce fungal inoculum.

8. Chemical Control:

• Treat seed tubers with Carbendazim 50% WP @ 2-3g/kg seed before planting.
• Use Fluopyram 17.7% + Tebuconazole 17.7% SC @ 1 ml/liter of water as a foliar spray to manage soilborne infections.
• Azoxystrobin 23% SC @ 1 ml/liter of water as a soil drench to reduce fungal inoculum.
• Validamycin 3% L @ 2 ml/liter of water for preventive soil treatment.

9. Trade Names of Chemicals:

• Bavistin (Carbendazim 50% WP) – BASF.
• Luna Experience (Fluopyram 17.7% + Tebuconazole 17.7% SC) – Bayer.
• Amistar (Azoxystrobin 23% SC) – Syngenta.
• Validacin (Validamycin 3% L) – Tata Rallis.

By implementing these management practices, Black Scurf of potato can be effectively controlled, improving crop health, yield, and marketability of tubers.

Black Scurf of potato:

1. Disease Name: Black Scurf of Potato

2. Causal Organism:

Rhizoctonia solani (fungus)

3. Affecting Stage:

• Affects the crop during the sprouting, vegetative, and tuberization stages.
• Primarily seen on tubers at harvest and during storage.

4. Symptoms:

Stem and Leaf Symptoms: 

• Poor emergence or irregular growth of plants due to damage to emerging sprouts.
• Dark brown lesions or cankers on the stem near the soil line, causing plant stunting.
• Severe infections may cause wilting, yellowing of lower leaves, and plant death.

 Tuber Symptoms: 

• Presence of black, hard, crust-like structures (sclerotia) on the tuber surface, giving it a rough appearance.
• Tuber infections may not penetrate deeply but can affect the marketability.
• In storage, infected tubers may develop dry rot or shriveling over time.

5. Favourable Conditions:

• Cool and moist soil conditions during sprouting and tuber formation.
• Poor soil drainage or waterlogging.
• Use of disease infected seed tubers or planting in infested fields.
• Dense planting and poor crop rotation practices.

6. Cultural Control:

• Use certified, disease-free seed potatoes to prevent initial infections.
• Rotate crops with nonhost crops like cereals or legumes to break the disease cycle.
• Avoid planting in fields with a history of Rhizoctonia infection for 2-3 years.
• Practice proper soil drainage and avoid overwatering during the crop cycle.
• Ensure early planting in warmer soils to reduce disease severity.
• Harvest tubers at the right maturity to minimize sclerotia formation.

7. Organic Controls:

• Treat seed tubers with Trichoderma viride or Pseudomonas fluorescens to suppress the pathogen.
• Apply well decomposed organic manure or compost to improve soil health.
• Use neem cake or other biofertilizers as a soil amendment to reduce fungal inoculum.

8. Chemical Control:

• Treat seed tubers with Carbendazim 50% WP @ 2-3g/kg seed before planting.
• Use Fluopyram 17.7% + Tebuconazole 17.7% SC @ 1 ml/liter of water as a foliar spray to manage soilborne infections.
• Azoxystrobin 23% SC @ 1 ml/liter of water as a soil drench to reduce fungal inoculum.
• Validamycin 3% L @ 2 ml/liter of water for preventive soil treatment.

9. Trade Names of Chemicals:

• Bavistin (Carbendazim 50% WP) – BASF.
• Luna Experience (Fluopyram 17.7% + Tebuconazole 17.7% SC) – Bayer.
• Amistar (Azoxystrobin 23% SC) – Syngenta.
• Validacin (Validamycin 3% L) – Tata Rallis.

By implementing these management practices, Black Scurf of potato can be effectively controlled, improving crop health, yield, and marketability of tubers.