Chlorothalonil (CAS: 1897-45-6) is a broad-spectrum, non-systemic protective fungicide. It appears as a white to off-white crystalline solid and acts through multi-site contact activity, which helps limit the development of resistance when used as directed.
It is formulated into suspensions, wettable powders, and granular products for control of leaf spots, blights, mildews, and other fungal diseases in agricultural and ornamental crops.
Technical-grade material is commonly supplied at about 98% purity for formulation and crop-protection use.