Pathogen Information
Downy mildew is caused by Pseudoperonospora cubensis a fungi like pathogen that can such symptoms such as:
- Yellow spots forming on older leaves
- leaves curl upwards and die off
- Stem maybecome discolored an die back
- White/grey growth on underside of leaves
Environmental Conditions
- Temperature: 70-80°F
- Humidity: Prolonged periods of wetness
- Most effected species: Cucurbitaceae
Disease Progression
Early Stage
leaves curl upwards with yellow spots
Mid Stage
White/grey mold forming on the underside of the leaves
Late Stage
Yellow leaves become necrotic defoliation occurs. effected fruit may wither
Prevention Methods
- Avoid overhead irrigation
- Maintain proper plant spacing
- Remove and destroy infected plant debris
- Use disease-free seeds and resistant varieties
- Keep leaves dry and improve air circulation
Treatment Options
- mefenoxam-based fungicide
- Chlorothalonil-based fungicides
- Neem oil treatments
- Copper-based fungicides
