by Mark VanGessel, Extension Weed Specialist; mjv@udel.edu
Fall herbicide treatments have a nice fit for many situations such as small grain weed control, assisting with cover crop management, and reducing the severity of weed infestations for no till corn or soybeans.
Let’s look at each of these situations. Treating small grain fields with a late fall herbicide application has worked well in our trials. As discussed in earlier newsletters there are no herbicides labeled for applications at planting (a preemergence application). As a result we have lots of winter annuals that emerge with or shortly after the crop. Waiting until spring to control these weeds often results in poor control because the weeds are large, and often stressed from the winter weather. On the other hand, an application in the late fall is made while the weeds are relatively small and actively growing. Remember these weeds are winter annual and will continue to grow after a few hard frosts, and the soil temperatures allow for significant growth through the month of November. If there is a lot of spring emergence, then those weeds can be controlled with a herbicide applied in combination with spring nitrogen applications.
Source: Read more from Weekly Crop Update
