Erysiphe polygoni

Fungal Disease

Erysiphe polygoni

Fungal Disease

Erysiphe polygoni

Fungal Disease

Powdery mildew, caused by the fungus Erysiphe polygoni, is a critical disease affecting cumin crops, particularly in regions like North Gujarat, where it can lead to significant yield losses. Below is a comprehensive overview of the disease, its symptoms, causes, and management strategies.

1. Introduction to Powdery Mildew

• Pathogen: Erysiphe polygoni.
• Impact:
  • Reported losses of 19.1% in North Gujarat (Gohil et al., 1988).
  • In severe cases, it may lead to complete crop failure.
• Prevalence:
  • Occurs primarily during February-March when the cumin crop is at the flowering stage.
  • Favored by cloudy weather and high humidity conditions.

2. Symptoms

• Initial Signs:
  • Powdery, white fungal growth appears first on leaves.
• Progression:
  • The powdery growth spreads to stems, branches, and flowers.
  • Severe infection can result in reduced photosynthesis, weakened plants, and poor seed yield.

3. Disease Cycle

• Primary Infection:
  • Occurs through infected soil and seeds carrying the fungal spores.
• Secondary Infection:
  • Conidia (fungal spores) are dispersed by rain splashes and wind, spreading the disease across the crop.

4. Favorable Conditions for Disease Development

• Temperature:
  • Cool weather with temperatures ranging from 20-25°C.
• Humidity:
  • High relative humidity (RH) exceeding 80%.
• Weather:
  • Cloudy conditions are highly conducive to the germination of conidia and subsequent disease development.

5. Economic Importance

• Powdery mildew can significantly reduce seed yield and quality.
• Farmers often resort to routine fungicide applications from one month of crop growth to maturity to mitigate losses.