Paddy Diseases
Sheath Blight
Symptoms
- The fungus affects the crop from tillering to heading stage.
- Initial symptoms are noticed on leaf sheaths near water level.
- On the leaf sheath oval or elliptical or irregular greenish grey spots are formed.
- As the spots enlarge, the centre becomes greyish white with an irregular blackish brown or purple brown border.
- Lesions on the upper parts of plants extend rapidly coalesing with each other to cover entire tillers from the water line to the flag leaf.
- The presence of several large lesions on a leaf sheath usually causes death of the whole leaf,
- In severe cases all the leaves of a plant may be blighted in this way.
- The infection extends to the inner sheaths resulting in death of the entire plant.
- Older plants are highly susceptible.
- Plants heavily infected in the early heading and grain filling growth stages produce poorly filled grain, especially in the lower part of the panicle..
Favourable conditions:
- Presence of sclerotia or infection bodies floating on the water
- Presence of the sclerotia in the soil
- Relative humidity from 96 to 100%
- Temperature from 28-32 °c
- High levels of nitrogen fertilizer
- High seeding rate or closing plant spacing
- Frequent rain
Management
- Apply organic amendments viz., neem cake @ 60Kg/ac or FYM 5 tonnes/ha.
- Avoid flow of irrigation water from infected fields to healthy fields. .
- Deep ploughing in summer and burning of stubbles.
- Spray Carbendazim 200g /ac. Soil application of B. subtilis @ of 1 kg/ac after 30 days of transplanting.
(The product should be mixed with 20 kg of FYM/Sand and applied).
Foliar spray at 0.2% at boot leaf stage and 10 days later.(400 g/ac).
|
Fungicide |
Dosage |
|---|---|
|
4 kg/acre |
|
|
200g/acre |
|
|
Bacillus Thuringiensis var. Kurstaki Serotype 3a, 3b, SA II WG |
1kg/acre soil application |
