Plant guide:ð Pumpkin
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Fungal
Downy Mildew on Pumpkin
Commonly affects: Cucurbita pepo, C. maxima, C. moschata (Pumpkin)
Yellow, angular patches bounded by leaf veins appear on the upper leaf surface, with a grey-purple fuzzy growth on the underside directly beneath. Unlike powdery mildew, lesions are angular rather than circular and follow the leaf's vein pattern.
Potential Causes
- 1Pseudoperonospora cubensis, an airborne water mould that travels long distances on wind
- 2Extended periods of leaf wetness from rain, dew, or overhead irrigation
- 3Cool nights combined with warm, humid days
Solution Steps
- 1Remove and destroy affected leaves promptly to limit spore production.
- 2Water at the base only and avoid overhead irrigation, especially in the evening.
- 3Apply a copper-based or chlorothalonil fungicide preventively if downy mildew is active in your region.
- 4Improve airflow between plants to help foliage dry faster after rain or dew.
Prevention Tip
Downy mildew spores travel on wind currents from other infected fields, so regional outbreak tracking (where available) helps time preventive fungicide applications before it reaches your garden.
