Fungicides are chemical compounds used to kill or inhibit the growth of fungi or fungi spores (they are considered a pesticide). Fungi are of special concern in agriculture as they can cause significant damage in plants. As with other pesticides, many fungicides can have negative human health impacts both from application exposure, pesticide drift, and as residues on food.
The Purdue Extension Office has developed a fact sheet for organic gardeners on the use of organic fungicides: Using Organic Fungicides