Symptom

• Irregular to angular pale translucent lesions bound by veinlets and grey powdery growth appear on lower surface of leaf
• Correspondingly light green specks appear on the upper surface of leaves.
• In severe cases whitish grey powdery growth appear on upper surface. The affected leaves dry up inward, turn yellow and fall prematurely.

• The pathogen survives during summer in the infected crop residues. The perennial cotton plants and self-sown cotton plants also harbour the pathogen.
• Primary spread is through conidia from infected plant debris.
• Secondary spread is through wind, rain splash, irrigation water and implements.

• Wet humid conditions during winter cotton season
• Intermittent rains during North-East monsoon season
• Low temperature (20-30 0C) during October-January
• Close planting
• Excessive application of nitrogenous fertilizers
• Very early sowing or very late sowing of cotton

• Remove and burn the infected crop residues.
• Remove the self-sown cotton plants during summer months.
• Avoid excessive application of nitrogenous fertilizers/manures.
• Adopt correct spacing based on soil conditions and varieties.
• Spray Wettable sulphur @ 400 g /acre or Chlorothalonil@ 200 g / acre or Difenaconazole @ 100 ml or Kresoxim Methyl @ 200 ml/ acre or Tebuconazole @ 200 ml/ acre or Propiconazole @ 200 ml/acre or Metiram 55% + Pyraclostrobin 5% WG @ 200g/ acre or Azoxystrobin 18.2% + Difenoconazole 11.4% w/w SC 200ml/ acre at 60, 90 and 120 days after sowing.

• Online resources
• CPG 2020