Sulfonylurea Herbicides causes yellowing or purpling of plants. These herbicides can either be pre-emergent or post-emergent herbicides and are systemic or work on the leaf surface. They are in the ALS (Inhibitors of acetolactase synthase ) group. ALS inhibitors stop cell division and growth by inhibiting the biosynthesis of the essential amino acids .
This class of herbicide works well in soil of low pH, it absorbs easier and is more persistent. This type of herbicide was introduced in the 1982 by Dupont chemicals