Fungicide #1 is a concentrated blend of peracetic acid and hydrogen peroxide – for treating mildew. It is recommended for destroying any mildew that develops on grapes shortly before harvest. Fungicide #1 is very reactive and quickly decomposes to acetic acid (vinegar), oxygen, and water. It leaves no persistent residue and is therefore safe for use up to the time of harvest. Peracetic acid is also widely used as a sanitizer for the brewing industry, as well as in dairy and meat processing.