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Downy Mildew on Zucchini: Act Fast to Save the Crop

Sudden spotting on zucchini leaves in warm, humid weather is classic downy mildew. It spreads rapidly and can kill the plant.

Spray immediately with chlorothalonil (e.g., Daconil) to slow the disease. Remove severely infected leaves. Improve air circulation and avoid overhead watering. For future plantings, choose resistant varieties and space plants widely.

About Gardening: Diagnosing and Treating Squash Vine Decline; Mystery Squash: Is It a Spaghetti Squash-Zucchini Hybrid?; Sudden Squash Death: Squash Vine Borer Suspect; First-Year Squash Problems: Speckled Leaves, Yellow Fruit, Rotting; Zucchini Leaves Turning Brown with Bugs? Likely Vine Borers—Act Fast; Why Zucchini Plants Flower But Don't Produce Fruit; Powdery Mildew on Summer Squash: Baking Soda Spray and Milk Treatment; Diagnosing Squash Vine Collapse: Borers, Wilt, and Bugs; Downy Mildew: Cool-Weather Obligate Parasites of Ornamentals; Choosing Mildew-Resistant Phlox for Hassle-Free Perennials

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