Thursday, June 24, 2021

Use crop rotation to help manage problematic weeds

Including corn in a crop rotation provides growers with a great opportunity to get a handle on problematic weeds, such as Palmer amaranth. Field Crop Agent, Anthony Growe, tells us how in this short video:

Corn is a very competitive crop and when it’s planted on narrow row spacings, 30 inches or even down to 20 inches, canopy closure will be achieved earlier in the season. This will shade out the row middles sooner, which aids in weed control.

In addition to corn’s competitive nature, growers can also use some herbicide chemistries not typically used in cotton, peanuts or soybeans. Herbicide products including atrazine and HPPD inhibitors, such as mesotrione, have activity on a broad spectrum of weeds and offer some flexibility for pre- or post-emergence applications.

One thing to be cognizant of is the over-reliance on our Group 15 chemistries, such as S-metolachor. These products are used extensively in soybeans, so it’s important that we preserve their efficacy by tankmixing other modes of action when possible.

Remember, to have a sound weed control program, we need to:

1) Start clean with a burndown or spring tillage.

2) Stay clean with pre and post-emergence applications utilizing atrazine and HPPD inhibitors.

3) Keep clean in the future by rotating our modes of action, using tankmixes, and overlapping residuals to help combat herbicide resistance.

This video was sponsored by the Corn Growers Association of North Carolina.

North Carolina State University contributed this article.

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