High Severity
Late Blight
Phytophthora infestans
A destructive disease causing rapid plant collapse in cool wet conditions.
Cause
Caused by Phytophthora infestans, an oomycete pathogen. Spreads rapidly under wet cool conditions.
Symptoms
- Water-soaked lesions on leaves and stems
- White fuzzy sporulation on underside of leaves
- Dark brown rot on fruits
- Rapid whole-plant collapse
Treatment Steps
- 1Apply preventive fungicide at first sign
- 2Remove and destroy infected plant material
- 3Avoid working in field when plants are wet
- 4Apply copper or mancozeb every 5–7 days
Prevention Tips
- Apply copper fungicide preventively before wet weather
- Avoid overhead irrigation
- Improve field drainage
- Monitor weather forecasts for infection risk
