A chlorinated aromatic fungicide, chlorothalonil is also known as tetrachloroisphthalonitrile in scientific circles. Chlorothalonil, a fungicide of the organochlorine class, is frequently used in agriculture to prevent fungal diseases in crops. For many years, a synthetic fungicide called chlorothalonil has been widely used to inhibit the growth of mould, mildew, rust, and blight. It is widely used in Germany in horticultural crops, vegetables, and grains. In Germany, horticultural crops, vegetables, and grains all make great use of it.