Pathogen :
- Mycelium - non-septate, inter cellular, systemic and obligate
- Conidiophores are erect, fragile, hyaline usually dichotomously branched
- Sporangia germinate directly and infect the plants
- Oospores are spherical, thick walled and deep brown
Mode of spread :
- Primary spread through oospores in soil and seed-borne .
- Secondary spread by conidia / sporangia
Favourable Conditions :
- Temperature ranging from 24-26o C.
- Continuous drizzling / rainfall.
- Relative humidity more than 80 %
Management:
- Use disease free healthy seeds.
- Drying seed to less than 14% moisture .
- Deep tillage and crop rotations for more than three years
- Roguing of diseased plants and alternate grass hosts
- Use disease resistance hybrids viz., TNAU COH(M)6, COH(M)8 and COH(M)11
- Seed treatment with metalaxyl @ 6g/kg of seeds
- Foliar spray with metalaxyl + mancozeb @ 1000 g or mancozeb 1000 g/ha after initial symptom / 20 DAP and 40 DAP
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Chlorotic streaks on leaves |
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