It inhibits the catalysis of Acetolactate synthase (ALS) in the biosynthesis of Valine, Leucine and isoleucine & stops cell division of roots and kills weeds.

Chempa (Pyrazosulfuron-Ethyl 70% WDG) is a broad spectrum herbicide for paddy, which effectively controls major broadleaf weeds, Sedges and Grassy Weeds. It is a pre and early postemergence Herbicide which gives the longer duration of control by inhibiting shoot growth and killing the weeds.