Agricultural crops :: Cereals :: Rice
Sheath Rot
Causal organism: Sarocladium oryzae (Syn : Acrocylindrium oryzae)
Symptoms:
- Initial symptoms are noticed only on the upper most leaf sheath enclosing young panicles.
- The flag leaf sheath show oblong or irregular greyish brown spots.
- They enlarge and develop grey centre and brown margins covering major portions of the leaf sheath.
- The young panicles may remain within the sheath or emerge partially. The panicles rot and abundant whitish powdery fungal growth is formed inside the leaf sheath
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| Brown discolouration of boot leaf sheath |
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Pathogen:
- The fungus produces whitish, sparsely branched, septate mycelium.
- Conidia are hyaline, smooth, single celled and cylindrical in shape.
Favourable Conditions :
- Closer planting, high doses of nitrogen, high humidity and temperature around 25-30 C.
- Injuries made by leaf folder, brown plant hopper and mites increase infection.
Mode of Spread and Survival :
- Mainly through air-borne conidia and also seed-borne.
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Management:
- Spray Carbendazim 100g or Edifenphos 200ml or mancozeb 500 g /ac at boot leaf stage and 15 days later.
- Soil application of gypsum (200 kg/ac) in two splits.
- Application of NSKE 5% or neem oil 3 % or Ipomoea or prosopis leaf powder extract 10 Kg/ac.
First spray at boot leaf stage and second 15 days later.
Source of information:
- AICRIP rice, TNAU, Coimbatore Rice diseases- online resource, IRRI, Phillippines.
Acknowledgements:
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