Chlorothalonil, also known as 2,4,5,6-tetrachloro-1,3-phthalonitrile

Chlorothalonil, also known as 2,4,5,6-tetrachloro-1,3-phthalonitrile, with molecular formula C8Cl4N2, is a broad-spectrum protective fungicide. Chlorothalonil can interact with the glyceraldehyde triphosphate dehydrogenase in fungal cells and combine with the protein containing cysteine in the enzyme, thereby destroying the activity of the enzyme, causing the metabolism of the fungal cells to be destroyed and lose vitality. Chlorothalonil has no systemic absorption and conduction effect, but after spraying on plants, it can have good adhesion on the body surface, and it is not easy to be washed away by rainwater, so the efficacy period is longer.
On October 27, 2017, the list of carcinogens published by the World Health Organization's International Agency for Research on Cancer was preliminarily sorted out for reference, and chlorothalonil was included in the list of Class 2B carcinogens.