This week growers facing challenges with Palmer amaranth questioned whether it was due to the product, the environment and lack of rain, or a resistant weed. Several factors could be at play, notes a UNL weed scientist, who recommends starting with preemergence herbicides with residual activity to get the best control.
With cold, wet conditions in March, many producers may be facing a smaller than expected window for making their herbicide burndown applications in April. This makes timely applications now even more important to provide for a proper interval before planting this year.
Nine weed species in Nebraska have now evolved resistance to at least one group of herbicides. Six weed species — common ragweed, common waterhemp, marestail, kochia, giant ragweed, and Palmer amaranth — have confirmed resistance to glyphosate. Rotate herbicide sites of action and weed control practice to avoid contributing to this trend.