Bonide Sulfur Fungicide prevents fungal spores from germinating, so it is most effective before the disease develops. Repeat treatment at weekly intervals to maintain control. Bonide Sulfur Fungicide is a micronized dust that can be applied dry or mixed with water for a wet application. When spraying, use a good pressure sprayer and apply thoroughly to all leaf surfaces. When dusting (Dustin Mizer), apply in a uniform thin film of dust to all leaf surfaces and fruit. Bonide Sulfur Fungicide is specially formulated for safe use on berries, including gooseberry and raspberry as well as cherries, grapes, citrus, apples, cucurbits, apricots, and currants.