Function

• Herbicides fall into three major categories based on how they are used. Soil-applied herbicides are added to the soil in which unwanted plants grow. Foliar-applied formulas are dusted or sprayed on plant leaves, while soil- and foliar-applied combinations attack plants directly or through their roots.
  
  

Features

• Soil-applied herbicides work by blocking plant cell division, destroying the chlorophyll in the leaves, stunting new plant growth and by blocking the molecular transfer that takes place during photosynthesis. Soil and foliar applications stunt new growth and interfere with plant metabolism, while foliar herbicides destroy plant shoots, prevent cells from manufacturing energy and disrupt cell function, making photosynthesis impossible.
  
  

Considerations

• Some herbicides, such as Paraquat, affect only the parts of the plants they come into contact with and are ideally applied in a manner that ensures maximum contact with as many parts of the plants as possible. Other herbicides, such as Glyphosate, must travel from the leaves through the plant to be effective.