By Scout Nelson
Sunflower fields across many areas are reaching advanced growth stages, making it difficult to control weeds with some herbicide options. At this stage, weeds such as kochia, Palmer amaranth, waterhemp, and other broadleaf weeds can create challenges for current crops and future production plans.
Clarence Winter, SDSU Extension Agronomy Field Specialist and Eric Jones, highlighted that late season weed escapes provide important information for improving future weed management decisions. These weeds can add more seeds to the soil, creating larger problems in future growing seasons.
Weed species such as Palmer amaranth, waterhemp, and kochia are especially concerning because they can produce large amounts of seeds and may develop resistance to commonly used herbicides. Sunflower production can make weed control more challenging because postemergence treatment options are limited once weeds become established.
Residual herbicides are an important tool for managing difficult weeds, but they work best when applied before weeds emerge. Producers should plan these applications carefully by considering crop growth stage, weed development, herbicide labels, and rainfall conditions needed for proper activation.
A successful weed management program should focus on prevention rather than trying to control weeds after they appear. Using only one herbicide application or one active ingredient can increase the risk of resistance. Instead, producers can use a combination of strategies to improve long-term weed control.
These strategies include crop rotation, using different herbicide groups, applying residual products at the right time, regularly scouting fields, and reducing weed seed production. Each practice plays an important role in protecting future crop yields and maintaining healthy fields.
Although some weed escapes cannot be prevented during the current growing season, they can provide valuable lessons. Producers should record where weeds survive, identify the species present, and review previous weed control programs.
Categories: South Dakota, Crops