Rainfed rice - IRRI books - International Rice Research Institute

Disease Management Strategies
Control measures
Use resistant varieties such as NC492 and CR1030 under rainfed lowland
conditions.
Balance fertiliser application and split the application of nitrogen.
Plow infected plant debris, self-sown plants and ratoons.
Use bleaching powder in the field water at 5 kg/ha.
Use seed treatment at a ratio of 1:l000 plantamycine or tetracycline to seed.
Use a foliar spray of streptocycline at 15 g/300 1 of water, agromycine 100
at 75 g/500 1 of water, plantamycine at 750 g/500 1 of water or cowdung
slurry at 1 kg/5 1 of water (600 1 slurry/ha).
Grow tolerant varieties such as Ajaya and PR-111 in endemic areas.
Rice tungro
This is caused by the rice tungro bacilliform virus
and rice tungro spherical virus. Plants infected at
seedling stage show a 10-40% reduction in yield.
The viruses are transmitted by the rice green
leafhopper (Nephotettix virescens). The incidence
of tungro disease correlates with the population of
insect vectors. Both viruses persist in rice and
several weed hosts. Ratoons from overwintered,
infected rice stubble serve as virus reservoirs.
Symptoms
Typical symptoms are stunting of plants and yellow or yellow-orange
discolouration of the leaves. Yellowing starts from the tip of the leaf and
may extend to the lower part of the leaf blade. Infected plants usually have
fewer tillers than healthy plants.
Control measures
Suppress the insect population in seedbeds by using insecticides or
adjusting planting dates.
Plant resistant cultivars. Rice tungro virus-resistant or moderately
resistant varieties that have gained acceptance are CNM539 and
CNM540 in West Bengal and IET7970 and Janaki in Bihar. Variety
Mahsuri is moderately susceptible.
Manage the vector through safe and non-resurgence insecticides using
both foliar spray (monocrotophos) and furadan granule application with
urea in moist soil in the ratio of 1:300.
Conduct vector surveillance and monitor the migration of the vector from
surrounding areas/regions.
Prepared by:
J. Kurnar and U. S. Singh
257