Weeds in Mississippi
How can I control hemp dogbane?
Hemp dogbane (Apocynum cannabinum L.) is a milky sap producing, perennial broadleaf weed in the dogbane family. This weed and other members of this genus are highly toxic. Although this plant has been reported to have potential uses for fiber production, or medicinal compounds, it is a problem weed in many fields in Mississippi.
Labels of several herbicides registered for use in corn, indicate hemp dogbane control. However the rates required for complete control may be higher than can be applied to corn either as a labeling restriction or to prevent crop injury. For this reason, postharvest treatments will likely be the ideal strategy for control. Harvest corn early enough to allow injured dogbane plants to recover from shock that may have occured from equipment injury or to regenerate above ground vegetation. Effective herbicides include Banvel (2 quarts per acre applied when most plants are at or beyond full bloom) or Roundup Ultra (4 quarts per acre or 2 percent solution applied at late bud to flower stage).
Other herbicide labels indicate hemp dogbane suppression. These include Banvel (1 to 2 pints per acre), Basis Gold (14 ounces per acre applied before weeds exceed 4 inches tall), and some formulations of 2,4-D (high rates and/or multiple applications).