Thiazopyr is primarily used as a pre-emergent herbicide in agricultural settings. It controls annual grasses and certain broadleaf weeds by inhibiting root development in germinating seeds. It is commonly applied in crops such as tomatoes, lettuce, and strawberries, especially in regions where soil-borne weeds pose a threat to young plants. Thiazopyr is valued for its selective action, allowing crop establishment while suppressing weed competition early in the growing season. Its application is typically done through soil incorporation before planting, ensuring effective root zone activity. Due to its mode of action and residual control, it helps reduce the need for post-emergent herbicide treatments, supporting integrated weed management programs.