Selecting Herbicide Crop Science Effective weed control depends

Selecting Herbicide Crop Science

ØEffective weed control depends on selecting the right herbicide.

ØHerbicides are classified according to the way they destroy weeds.

Types of Herbicide §Contact Herbicide §Growth Regulators §Soil Sterilants

Contact Herbicide § Kills plants by exposure § Works best on Annuals § May only kill parts of the plant in contact

Growth Regulator § Alters growth or metabolic processes § Absorbed by the roots, stems, or leaves

FThe movement of a herbicide inside of a weed is known as translocation

Soil Sterilant §Prevents the growth of plants in the soil §Most useful in greenhouse

Selectivity of Herbicides

Selective Herbicide §Kills only certain plant species and not others

Selective Herbicide §Possible to spray in field without injuring crop

Non-Selective Herbicide §Kills all plants regardless of species

Non-Selective Herbicide §Should not be used in growing crops

Using Herbicides Time of Application

Herbicides may be applied at three times:

FPre-plant FPre-emergence FPost-emergence

Using Herbicides Area of Application

4 general areas of application are used:

Band § Treating narrow strips with herbicide § Used in cotton & corn

Broadcast §Treating the entire area of a field §Used with pastures §Not used in row crop

Directed Appl. §Treating only selected or targeted plants §Some use in row crop §Used a lot with trees

Spot Application §Treating only certain areas in field §Saves cost plus labor §Protects environment

Applying Herbicide §Knowing when and how to apply are important for effective weed control