Dr. Earth Final Stop 24 oz. Concentrate Organic Disease Control Fungicide. This all-natural and highly effective solution kills and controls powdery mildew and other mold on contact, providing weeks of continued protection. Safe for use in gardens, it has a maximum coverage area of 5000 square feet and visible results can be seen within 72 hours. The active ingredient, Rosemary Oil, can be applied using a hose end sprayer.