Classification of Herbicides Based on Time of Application
a) Pre-Planting/ Pre-Sowing
v) Sodium Chloride
These herbicides are applied before a crop is planted are called pre-planting herbicides. The herbicides is usually incorporated into the soil to reduce volatility and photo decomposition. E. g Paraquat , Basalin.
b. Pre- Emergence Herbicides:
Pre-Emergence herbicides is most effective when applied before the emergence of crop and weeds or the term may also refer to herbicides use after weed has emerged or established but before crop emerge E ,g Simazine, Atrazine.
c. Post-Emergence Herbicides:
Post-Emergence herbicides are most effective applied after the emergence of crop and weeds or this term may also refer to herbicides use after crop has emerged but before weeds emerge. E. g 2,4-D , Dicamba ( Banvel) etc.