The time has come again to get rid of those pesky weeds that interfere with your planting season. This past harvest proved to be tough for getting crops out of the field, let alone applying herbicides to control winter annuals like marestail. One of the things we always encourage is to be on the look out for weeds when you are in the combine. Being able to take a mental note on where they are can help you attack them in the spring. We wanted to address some of the main things to keep in mind on your spring burndown program.
Ideally, farmers should apply burndown herbicide a couple weeks prior to planting, and if you weren’t able to apply herbicide last fall, you should consider a burndown treatment as soon as possible this spring. In a recent article, “What Farmers Need to Know About Burndown Herbicides,” by Gil Gullickson with Successful Farming, Joe Bolt, a Practical Farm Research (PFR) Operator and herbicide specialist for Beck’s Hybrids, was quoted on his burndown suggestions.
He advised us that the earlier the small weeds are gone, the better. He also added that burndown is critical for no-tillers. “If you don’t apply a burndown pass, you will get a weedy mess out there.” For farmers who incorporate some tillage, adding a burndown followed by vertical tillage can control weeds better than just a tillage pass. Also, planting into weedy fields, means you are likely to have uneven emergence.
Bolt also said, “If you don’t have time for a burndown and plan to till and then plant, put down a residual (herbicide) and then add something that has post activity- such as Gramoxone or Liberty.” If you think there will be some time before a burndown pass and planting, Bolt suggests using a herbicide with residual activity like Sharpen.
The problem with applying the usual burndown herbicide combo (2,4-D and dicamba), is that they have plant-back restrictions. These can range between 7 to 30 days depending on the application rate. When applying post-emergence in herbicide-tolerant soybean weed-management systems, most will use options already containing the same chemicals in XtendiMax/Engenia/Fexapan (dicamba) and Enlist Duo/Enlist One (2,4-D choline). When you are using the same site of action in burndown and pre-emergence as in post-emergence applications, this increases selection pressure on weeds.
Make sure you are selecting for resistance when applying herbicide and save the group 4 growth regulators for in-season use. There are plenty of options that now exist for post-emergence applications in soybeans. Bolt reminds us that, “Ten years ago, we didn’t have as many options.”
So, remember to incorporate a residual herbicide for your burndown applications. It can be very beneficial in combatting tough weeds such as marestail and giant ragweed. When applying the residual herbicide, it is important to allow enough time for residue decomposition before planting. For recommendations and proven to perform methods on a burndown program for your operation, contact the Novus Ag office at 937-349-2080.