Types

• There are many types of herbicides, and each has its own mode of action. The most important types of herbicides fall into the general classifications of auxin mimics, amino acid inhibitors, lipid biosynthesis inhibitors, chlorophyll or carotenoid inhibitors, cell membrane destroyers, photosynthetic inhibitors and shoot and root inhibitors.
  
  

Function

• Auxin mimics act by mimicking the plant hormone auxin and triggering unsustainable growth to kill the plant. Amino acid inhibitors and lipid biosynthesis inhibitors work by binding to a key enzyme to prevent the synthesis of essential molecules the plant needs. Cell membrane destroyers disrupt cell membranes, while photosynthesis inhibitors prevent photosynthesis and root and shoot killers disrupt cell division in fast-growing roots and shoots.
  
  

Considerations

• Some herbicides work on contact with leaves or stems, while others spread throughout the plant beginning in the leaves or the roots. Certain herbicides are more selective than others, meaning that they are designed to kill a narrower range of species.