Autumn can provide a new opportunity for pasture owners to manage their perennial and biennial weeds. Iowa State University Extension and Outreach agronomist Meaghan Anderson is now offering insight into how individuals can prepare their fields for the upcoming winter.
Most herbicides that are used in pastures are growth regulator herbicides. Typically, the products that contain picloram and aminopyralid are more expensive, but they provide more effective long-term control of perennials. Before pasture owners begin, they should scout the area to identify target weeds and their primary locations. By being more specific with herbicide application, pasture owners can avoid applying the product to areas that may not need it.
Pasture owners should always read their herbicide labels carefully to identify which weeds can be controlled, appropriate rates, and any restrictions for treated locations. Herbicide residue can potentially damage sensitive plants. Users should also keep in mind that herbicide can still be effective after a frost, assuming weed foliage is still active. Applications should be made on sunny days when the daytime temperature is around 50 degrees Fahrenheit. The treatment will control legumes that have interseeded with grass as well.
Anderson notes that understanding why weeds are thriving in a field can provide insight into how to control them in the future. While herbicides are valuable and effective, good management practices can limit the need for them. A healthy sod can help prevent weeds from establishing themselves as well.