We are now approaching the end of October and harvest is toward the tail end in a lot of geographies. It has been up and down as far as yields go. As we near the end of harvest we need to start thinking of next spring and what practices can help us get out to a fast start in 2022. One practice that I am a fan of is a fall herbicide application to help put these fields to bed for the winter.

Ideally a fall herbicide application should be made around mid-October. But with the off and on rain this fall, a lot of crops are still in the field. It is not too late for a fall burn down if sprayers can get in the field. Herbicides can be applied between daytime temperatures of 40-60 degrees Fahrenheit, but weeds will die slower at the cooler temperatures. At lower temperatures, translocation and absorption of 2,4-D and glyphosate are slowed.

Controlling Marestail

Marestail (horseweed) is one of the main weeds we are targeting. Once their seeds fall to the ground from a plant this fall, they can germinate immediately. When you consider the high marestail populations we have across the Midwest, that would be a lot of marestail. So controlling those populations, whether that be with tillage or a herbicide, is critical. We all know planting windows can be short in the spring and the higher weed population we have out there the longer the soil will take to dry and warm up. The picture below is a photo I took a few years ago and it illustrates the benefit of a fall burndown perfectly. You see the area to the left of the yellow line was missing by the sprayer while the area to the right was not. You can see the difference in the marestail population the following spring.

Results from Michigan State University Extension weed scientist Christy Sprague’s research in no-till soybeans found that fall applications of 2,4-D, dicamba, or Sharpen will control fall emerged marestail and are cost-effective. Tank-mixtures with glyphosate are needed to control other winter annual and perennial weeds outside of marestail.

As we continue with harvest and begin November, remember to please contact your LG Seeds sales rep or agronomist with questions. We can help guide you through difficult decisions. Everyone please have a safe and successful harvest season.