Kochia is an issue with row crop production in the north central area of South Dakota. New Post-emergent options in corn and soybean have helped alleviate Kochia competition from many fields, but these herbicide options shouldn’t be completely relied upon for a long term plan for control. One option is to use a soil residual herbicide applied in the fall on fields that will be planted to cash crops such as corn or soybeans the following year. The weather in parts of South Dakota can limit the opportunity to fully activate Pre-herbicides applied before planting in the spring. This opens the door for using herbicides in the fall to control not only winter annuals and biennials, but give the advantage over early emerging summer annual weeds like Kochia.
Herbicide active ingredients that could be applied in fall before corn would include atrazine, flumioxazin, flumioxazin+pyroxasulfone, pyroxasulfone, s-metolachlor, acetochlor or a combination of these. Herbicide active ingredients that could be applied in fall before soybean would include flumioxazin, pendimethalin, s-metolachlor, dimethenamid-p, pyroxasulfone, sulfentrazone, saflufenacil, dimethenamid or a combination of these products. With each of these products, make sure to pay attention to environmental conditions required for application as specified in the label. These products give opportunity in the fall to apply them after harvest, most years and situations across dryer areas of the state.