Sheath Rot Disease of Rice: Causes, Symptoms & Control Measures

Disease Overview :

• Causal Organism: Sarocladium oryzae (fungus)
• Affecting Stage: Booting to heading stage (leaf sheaths surrounding panicle)
• Symptoms: Greyish-brown lesions, rotting, and disintegration of leaf sheaths

Symptoms :

1. Initial lesions on uppermost leaf sheaths
2. Lesions turn brown with dark margins
3. Infected sheath rotting and disintegration
4. Panicles trapped inside infected sheath
5. Poor grain filling and chaffy grains
6. Greyish-white powdery fungal mass in severe cases

Favorable Conditions :

• High humidity and warm temperatures (20-30°C)
• Frequent rainfall and cloudy weather
• Excessive nitrogen fertilizers
• Dense crop stands and poor drainage

Control Measures :

Cultural Control –

1. Use resistant varieties (ADT-37, CR-1009, IR-20)
2. Proper water management and drainage
3. Balanced nitrogen fertilizer application
4. Crop rotation with non-host crops
5. Remove infected debris

Organic Control –

1. Trichoderma harzianum or Pseudomonas fluorescens biocontrol agents
2. Neem oil sprays or neem-based bio-pesticides
3. Compost tea or cow urine-based bio-extracts

Chemical Control –

1. Hexaconazole 5% SC (Contaf – Tata Rallis)
2. Propiconazole 25% EC (Tilt – Syngenta)
3. Carbendazim 50% WP (Bavistin – BASF)
4. Mancozeb 75% WP (Dithane M-45 – Indofil)

Effective Management –

By implementing these strategies, farmers can effectively manage sheath rot disease, minimize yield loss, and improve grain quality, ultimately enhancing crop resilience and productivity.