Cassava Root Rot: An Emerging Problem in Kerala

Cassava plants in certain areas of Kerala show yellowing and drying of leaves; rotting of tubers and collar region of the stems. The cassava tuber rot hitherto reported showed symptom only on tubers, not in foliage. Farmers revealed 40-80% of this disease incidence where cassava is grown in low land paddy fields of Kollam district and less than 10% in Thiruvananthapuram district. This disease is now reported only from low land cultivation.

Symptoms

There are three stages ·

1. Decaying of setts along with collar region before rooting immediately after planting.
2. After 2-3 months, yellowing and drooping of old leaves and rotting of stem and tuber which affects tuber development.
3. After 6 months, decaying of stems in the collar region near soil and rotting of all or part of tubers.

Spread

Through planting material, soil, water and other farm tools.

Action taken

Initiated research on etiology and management at ICAR-CTCRI, Thiruvananthapuram.

Adhoc Recommendations

• Strict sanitation of the field: Removal and burning of highly infected plants.
• Crop rotation with suitable crops in two years.
• Avoid water stagnation: Ensure good drainage in the field.
• Application of Lime @ 150 to 250 g per plant 10- 15 days before planting, where pH of the soil is 4-5 (Ensure soil moisture during application).
• Use only healthy setts and avoid setts from infected fields.
• Application of Neem cake @ 20 g per plant.
• Application of Trichoderma asperellum enriched FYM @ one kg per plant (Multiplied by mixing 2.5 kg Trichoderma with 100 kg of Farmyard manure (FYM) and then mixed with 12 tonnes of FYM for one hectare) (or) 50 g of Trichoderma enriched manure (1 kg Trichoderma mixed with 100 kg of FYM or vermicompost). ·
• Sett treatment with Carbendazim (0.1 %) (or) combination of Carbendazim and Mancozeb (0.2%) for 10 minutes.
• Drenching with the same fungicides starting from planting three times at 15 days interval.

Read more: http://www.ctcri.org/focus/Cassava%20root%20rot%20Adhoc%20recommendations_CTCRI.pdf

Original link : http://www.ctcri.org/