Controlling Powdery Mildew on Zucchini: Sanitation and Sprays

Introduction

Powdery mildew on cucurbits is a fungal issue, not soil-borne.

Mildew is Fungus, Not Soil-Borne

Spores overwinter on plant debris.

End-of-Season Cleanup

Destroy infected plants and all ground debris.

Air Circulation and Full Sun

Space plants, avoid shade to reduce humidity.

Sprays: Sulfur, Neem Oil, Baking Soda

Weekly spray: sulfur, neem, or 1 tbsp baking soda/gallon water until spread stops or humidity drops.

Conclusion

Sanitation, airflow, and weekly sprays control powdery mildew.