prothioconazole

**Prothioconazole** is a systemic, broad-spectrum triazolinthione fungicide primarily used for the control of fungal diseases in cereal and other field crops. It acts as a **demethylation inhibitor (DMI)**, specifically inhibiting the fungal enzyme **sterol 14α-demethylase (CYP51)**, a cytochrome P450 enzyme essential for ergosterol biosynthesis, which is a key structural component of fungal cell membranes[1][5][13][16][18]. The fungicidal activity is predominantly attributed to its primary metabolite, **prothioconazole-desthio**, which potently and non-competitively inhibits CYP51 by binding to the heme group and preventing ergosterol formation, thus compromising fungal cell membrane integrity and function[5][18]. **Prothioconazole** is marketed as a solo active ingredient (e.g., Proline) and in various mixture products (e.g., Delaro Complete, Prosaro), controlling diseases such as Fusarium head blight, rusts, powdery mildew, and septoria leaf spot[3][16][18]. Developed by **Bayer CropScience** and introduced in 2004, it quickly became a key tool in cereal disease management[13].

Brand names

ProlineProthioconazole 4L SelectProthioconazole4L SelectProthioconazole-4L SelectProthioconazole 480 SCProthioconazole480 SCProthioconazole-480 SCDelaro Complete (in combination)Prosaro (in combination)

Other names

prothioconazole-desthio (major metabolite)triazolinthione fungicide