Copper sulfate is an inorganic compound that combines sulfur with copper. It can kill bacteria, algae, roots, plants, snails, and fungi. The toxicity of copper sulfate depends on the copper content.Copper sulfate is used as a fungicide, algaecide, root killer, and herbicide in both agriculture and non-agricultural settings. It is also used as an antimicrobial and molluscicide. Uses for individual products containing copper sulfate vary widely. Always read and follow the label when applying pesticide products.