Which herbicides inhibit the acetolactate synthase enzyme?

The herbicides that inhibit the acetolactate synthase (ALS) enzyme are known as ALS inhibitors. This class of herbicides disrupts a critical step in the biosynthesis of branched-chain amino acids—valine, leucine, and isoleucine—by targeting the ALS enzyme. When this enzyme is inhibited, plants cannot produce these essential amino acids, ultimately leading to their death.

ALS inhibitors are particularly effective against a wide range of broadleaf and grass weeds, making them a valuable tool in integrated pest management. They are often selective in their action, allowing for the control of targeted weed species while minimizing harm to desirable crop plants. Since other options like EPSP synthase inhibitors, photosynthesis inhibitors, and growth regulators target different processes within plants, they do not specifically impact the activity of ALS, thus reinforcing why ALS inhibitors are identified as the correct answer in this context.