Rainfed rice - IRRI books - International Rice Research Institute

RAINFED RICE A SOURCEBOOK OF BEST PRACTICES AND STRATEGIES IN EASTERN INDIA
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between glumes. Low maximum temperature accompanied by high relative
humidity at flowering and also high nitrogen favour the disease.
Control measures
Follow sanitation practices by manually removing spore balls before
harvesting.
Apply balanced nitrogen.
Use varieties that are moderately resistant such as Bala, Kaveri and
Hamsa.
Apply mancozeb using a spray at heading.
This is now a major
disease with the
introduction of
modern varieties.
Sheath rot (caused by Sarocladium oryzae )
Symptoms
Rot occurs on the uppermost leaf sheaths
enclosing the young panicles. These panicles
remain in the sheath or emerge only partially.
Panicles that have not emerged tend to rot.
Control measures
Plant rice early to avoid infection.
Plant resistant or moderately resistant varieties under rainfed lowland
systems, such as NC492 and CR1030.
Use a spray application of carbendazim at tillering and boot leaf stage.
Bacterial blight
(caused by Xanthomonas campestris
pv. oryzae )
Infected plants produce fewer and lighter grains
and the grains are of poor quality. Kresek can lead
to total crop failure. Infected rice seeds can carry
the bacterium until the following crop season, but
the disease originates mainly from other sources
such as straw, stubble, volunteer plants, ratoons,
wild rice or susceptible weeds. The disease results
from high temperatures, high rates of nitrogenous
fertilisers and phosphorus and potassium
deficiency.
Symptoms
The disease has two phases of infection:
1. Elongated white lesions on the leaves (leaf blight) and
2. Systemic infection that wilts the entire young plant (kresek).