Marysville, OH: An untreated check shows the impact weeds can have on corn. Notice the smaller, paler corn plants (right) versus the corn plants (left) in the cleaner plot.

Prepare your weed management strategy for this season by taking a look back at the tough driver weeds that disrupted your corn and soybean fields last season. Giant ragweed, Palmer amaranth and waterhemp were commonly named as the most troublesome weeds, followed closely by marestail and morningglory.

During harvest last year, you may have experienced some escaped weeds, indicating species of weeds that weren’t adequately managed during the season. This could have resulted from a number of factors including:

• Ineffective sites of action (SOAs) within the herbicide program that was applied.
• Delayed herbicide application timing.
• Presence or development of herbicide resistance.

Weed escapes often result in weeds going to seed, leading to an increase in the number of seeds deposited into the weed seed bank. The University of Minnesota extension says if escaped weeds have the ability to produce seed, they have the potential to stick around for decades. To manage problem weeds that successfully escaped last year, adjusting your weed management approach may help prevent this cycle from occurring again.

We recommend choosing corn and soybean herbicide programs that provide long-lasting residual control and contain multiple effective SOAs in both the pre- and post-emergence applications. This means the SOAs need to have activity on the tough driver weeds present in your field.

Corn solutions:

For your corn herbicide program, we recommend Acuron^® corn herbicide, which combines 4 active ingredients (AIs), including the unique AI bicyclopyrone, and 3 effective SOAs. The bicyclopyrone component of Acuron complements the other active ingredients and helps provide more consistent and reliable control of 70+ tough weeds. And, Acuron offers flexible application from 28 days preplant up to 12” corn.

The atrazine-free counterpart of Acuron, Acuron Flexi, has 3 active ingredients, 2 effective SOAs, and provides the same reliable safety and performance from 28 days preplant up to 30” corn. Acuron Flexi allows for the flexibility to add atrazine or glyphosate based on farming practice.

Soybean solutions:

For soybeans, we recommend a pre-emergence application of Boundary^® 6.5 EC or BroadAxe^® XC herbicides, both of which contain 2 effective SOAs. Those can be followed by Flexstar^® GT 3.5 herbicide as a post-emergence application for 2 additional SOAs.

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