Crop protection plans can’t be an afterthought

The 2022 growing season is just around the corner, and herbicide planning is more important than ever this year. In the previous issue of Today’s Farmer, MFA Director of Agronomy Doug Spaunhorst touched on potential supply chain challenges with some common herbicide products. In particular, supply looks to be tight for widely used products such as glyphosate, glufosinate and 2,4-D. There will likely be situations where we need to carefully look at a field’s weed spectrum to identify the need for these products and find alternative herbicides.

While glyphosate and glufosinate are used to control susceptible weeds that are already emerged, in 2022 it will be critical to prevent weed emergence from occurring in the first place. In addition to using these types of herbicides in our first pass, it will be equally important to use residual chemistry in our second pass for continued weed prevention. If we have successfully prevented new weed emergence and have a clean field three weeks after the first pass, we can apply the next round of residual herbicides and eliminate the need for herbi­cides that only control emerged weeds.

To determine the correct herbi­cides that will be required, thorough and timely scouting is essential ahead of both the burndown pass and the in-crop application. Many products used for the first herbicide application ahead of corn already contain active ingredients that have excellent activity on broadleaf weeds, including those that are difficult to control.

However, this is not necessarily the case for grass weeds. On the bright side, many common grass weeds can be controlled with a low­er rate of glyphosate than needed for broadleaf weed control.

For instance, giant foxtail up to 20 inches tall can be controlled at a 75% rate of most glyphosate products when compared to rates needed to control many broadleaf weeds. While MFA will never rec­ommend reducing rates required by label, this is an example that would reduce glyphosate usage while still using a full labeled rate to control a target weed.

Newer soybean herbicide traits offer additional opportunities to re­duce the use of herbicides that are likely to be in tight supply. While older formulations of 2,4-D may be hard to come by, availability of Enlist products looks favorable. In addition, there is no waiting period between Enlist applications and planting of Enlist-tolerant soybeans as there is with older 2,4-D for­mulations. In soybeans with Xtend or XtendFlex traits, Xtendimax or Engenia herbicides also provide excellent broadleaf weed activity.

Regardless of herbicide-tolerance traits, there are other options for grass control in soybeans. Herbi­cides commonly used in soybeans to control glyphosate-tolerant vol­unteer corn also control most grass weeds. These products are known as FOPs and DIMs due to the active ingredient names and can be used as a glyphosate alternative strictly for grass control in soybeans. In addition, corn hybrids with the Enlist trait will be tolerant to the FOP family of herbicides. Products such as Assure II may be used for in-crop grass weed control in corn with this trait.

By the time we enter the next growing season, there will likely be several more challenges related to crop protection supplies. Growers should have a cropping plan that includes residual herbicides to provide protection from weeds that have a history of showing up in each field. Pair that with frequent and thorough scouting to identify emerged weed species.

By following these practices, we can develop recommendations to provide proper weed control and prevention while helping to avoid potential supply issues. Your MFA manager, key account managers and local agronomists are here to help develop these plans and deliver weed-control solutions for your farm.