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

• The fungus produces whitish, sparsely branched, septate mycelium.
• Conidia are hyaline, smooth, single celled and cylindrical in shape.

• 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.

• Mainly through air-borne conidia and also seed-borne.

Management:

• Grow moderately resistant varieties viz., CO 55 and ADT 59..
• Treat the seeds with Thiram at 4 g/kg or Bacillus subtilis (TNAU) @ 10g/kg of seed.
• 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.

• IRRI, Phillippines

Acknowledgements: