The sheath rot disease is caused by complex fungal and bacterial pathogens.
Major pathogens are the bacteria (Pseudomonas fuscovaginae), and the fungus ( Sarocladium oryzae and Fusarium sp).
Brown color stains can be observed on the infected grains.
It is seed borne disease.
Symptom
Oblong or irregular shape lesions with dark reddish-brown margins and gray center on the flag leaf’s sheath. The lesions enlarge, merge and may cover the entire leaf sheath. If severely infected, panicles could not fully emerge, partially remain in the leaf sheath.
Whitish powdery growth inside the affected sheath and the rot panicle can be observed.
Unemerged panicles rot and turn red-brown to dark brown in color, covered with pinkish color fungus.
Source: Research Gate
Disease Cycle
It is air-borne disease.
The disease may infect into the rice plant from the stomata and the injuries caused by the insect.
Good Practices for Control
Clean the infested plant residues and stalks from the first season and remove them from the fields.
Due to the inoculum transmitted through the seed, use quality seed from the recommended seed dealers.
Chemical Control
Seed treatment with fungicides such as Mencozeb/ Benomyl can eliminate the seedborne inoculum.
Foliar spraying with Carbendazim 250g/ha or Endifenphos 1Lit/ha or
Chlorothalonil 1kg/ha at the time of panicle initiation reduces the infestation.
