Weeds
What controls 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 and medicinal compounds, it is a problem weed in many Mississippi soybean fields.
Currently there are no herbicides labeled for use in soybeans to control hemp dogbane. The diphenylether herbicides, such as Reflex, Cobra, and Blazer will burn the leaves and temporiarly stunt growth and development, but will not provide long-term control. Roundup Ultra, used in a Roundup Ready soybean system, should be a more effective treatment. Best results will probably occur with fall applications of Roundup Ultra using a spot treatment strategy with 1.5 percent by volume Roundup Ultra solution or 2 quarts Banvel per acre. However, soybean must be harvested early enough to allow hemp dogbane stems to regrow before herbicide applications.
Deep tillage that shears the main stems below the soil surface may also help provide long-term control.
