It’s hard to believe we are already talking about fall burndown. Just like seeing back-to-school ads in mid-July, isn’t it too early? All you have to do is remember one word: Marestail. There are at least 20 additional costly weeds that can be effectively controlled by a fall burndown application. Henbit, Pennycress, Dandelion and Shepherd’s Purse can be tough to control; but few of those make my heart rate jump like Marestail, largely because there are so few chances in spring to get a complete kill. Dicamba plus 2,4-D plus a residual product is our best shot in the fall to kill Marestail because of the translocation of the herbicides to the roots as the sugars in the plant carry the herbicides deep into the root reserves for winter. While we have a wide window, we want to make sure we hold off spraying until the soil temperatures start to stay down in the 50 degree range, preferably mid-October. Burndown prior to corn planted next spring is important, but not as critical as any field going into soybeans next spring. Our best herbicide choice, within a 2 week window of planting soybeans, for effective control of marestail is Sharpen® from BASF. However, this product pales in comparison to the efficacy of fall sprayed fields.
There are several choices of tank mixes to combine with your 2,4-D + Dicamba combo, yet we look at the keys to what sets them apart. One of the most versatile and effective options is Autumn™ Super from Bayer Crop Science. Not only do you have the flexibility to apply this herbicide before both corn and soybeans, but it also covers a huge spectrum of winter annuals while providing some residual control for other weeds ahead of planting. This benefit takes the pressure off of your spring herbicide applications and workload. One of the cautions with Autumn™ Super, as with many other ALS chemistries, is to avoid applying it to high pH soils. At 7.5 pH levels and higher, reduced rates must be used. At a pH of 8.0 and above, Autumn™ Super should not be used, but these are rare cases. Always read and follow label directions carefully.
Virtually all of the Marestail across our territory is glyphosate resistant, so we want to leave nothing to chance with your weed control program. Our goal at UFC is to have EVERY ridge-till or no-till field going into soybeans next spring be sprayed this fall. As your Field Sales Agronomist is out visiting with you prior to and during harvest, ask about Autumn™ Super and how it could fit into a total herbicide program.
Fall burndown, while being very important, is only one step in the weed control process. We will follow that fall application with a residual plus burndown combination at planting that will include an acetaniline or chloroacetamide product. This program, followed by a post emergence glyphosate combination, will give you the best chance of keeping both winter annuals and summer annuals out of your fields. Speaking of glyphosate resistance, another weed of concern in our trade territory is waterhemp. These resistant weeds are the reason why a residual product must be employed in your weaponry. Also, a .75 to 1 “irrigation must follow right behind the acetaniline or chloroacetamide products because of the incorporation necessary to PREVENT weeds from emerging in the first place. Ask your FSA about a weed control plan of attack that could involve Autumn™ Super and a fall burndown on your no-till and ridge till fields next time you see them.