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1. This is the most important and destructive disease of rice in all NE states causing yield losses up to 35-50%.
2. The fungus, Pyricularia grisea attacks all aerial parts of the plant at all stages of growth, although leaves, nodes and neck of the panicle are found to affect more commonly.
3. spindle shaped spots with ashy center and brown margin are typical symptoms appear on the leaves.
4. Many such spots unite resulting in larger irregular necrotic patches on leaf and in severe cases the affected fields give a blastedlbumt appearance. Hence the name blast has been given to this disease.
5. Symptoms also appear on leaf sheath, calm, calm node and glumes as dark brown or black coloured discolouration.
6. At the time of flower emergence, the neck of the panicle is infected, which becomes blackened and shriveled. This is called neck rot, panicle blast or more commonly neck blast. Neck infection in the early stage of crop growth leads to breaking of panicle and formation of chaffy grains, which results in maximum yield losses.
Control Measures of Rice last:
1. Destructing weed hosts present on the bunds/terraces of the field
2 . Applying fertilizer NPK @ 60:60:40 for high yield with low disease intensity and applying nitrogen in three equal split doses at i) a week after sowing, ii) at tillering stage and iii) at panicle initiation stage
3. Adjusting the dates of sowing. Early sown crop (April-May) has less foliar blast damage as compared to late sown crop (June-July).
4. Growing tolerant/resistant varieties to minimize the disease for maximum yields Soaking seeds for 24 hours in 0.1 % carbendazim solution prior to sowing in nursery beds or in a direct sown crop
5. Root dipping of rice seedlings for 12-16 hours in fungicidal solution of carbendazim @ 1 gllit can protect the transplanted plants up to 30-50 days after transplanting (DAT)
6. Spraying offungicides like Hinosan @ 1 mill or cabendazirn @ 1 g/l or Tricyclazole @ 0.6 g/l or Capropamid @1 mill with a sticker (Triton or Sandivit @ 0.1 %) is recommended