Dicamba

Dicamba (3,6-dichloro-2-methoxybenzoic acid) is a herbicide. Brand names for formulations of this herbicide include Banvel, Diablo, Oracle and Vanquish. This chemical compound is an organochloride and a derivative of benzoic acid.

Role as herbicide

Dicamba controls annual and perennial rose weeds in grain crops and highlands, and it is used to control brush and bracken in pastures, as well as legumes and cacti. It kills broadleaf weeds before and after they sprout. In combination with a phenoxy herbicide or with other herbicides, dicamba is used in pastures, range land, and noncrop areas (fence rows, roadways, and wastage) to control weeds. Dicamba is toxic to conifer species but is in general less toxic to grasses.

Dicamba functions by increasing plant growth rate. At sufficient concentrations, the plant outgrows its nutrient supplies and dies.

Resistance

Some weed species have developed resistance to dicamba. Dicamba resistance in Bassia scoparia was discovered in 1994 and has not been explained by common modes of resistance such as absorption, translocation, or metabolism.