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.
It's important to consider soybean growth stage and preharvest interval when applying postemergence herbicides to avoid potential crop injury. This article describes how to determine crop growth stage and includes a table of application restrictions for common postemergence herbicides.
When applying postemergence herbicides, consider corn growth stage, weed species present, and crop and weed heights. The article includes how to determine corn growth stage, recommendations to avoid problems, and a table of application restrictions for common postemergence herbicides.
Controlling glyphosate-resistant volunteer corn is a major challenge in some soybean fields this year as preemergence herbicides aren't very effective. Postemergence herbicides will be critical to its management.
Cool, wet soil conditions in late April and May may have enhanced the potential for soybean injury from PPO-inhibiting herbicides. The author describes plant injury symptoms to look for when scouting young soybean seedlings.