‘Keep the weeds guessing’

Draft a weed-control plan before planting, don’t skimp on preplant treatments and rotate modes of action.

Valent residual control
The soybeans on the left were untreated; the ones on the right received an application of Valor 30 days prior to the photograph.

Soybeans are expected to see another low point in commodity prices this year, but that won’t change the pre-planting habits of Mid-South growers, such as Jim Sayle. He’s a believer in applying a pre-emergence residual herbicide at the start of the season to avoid gambling with his yield.

“If I skimp on my fertilizer, chemical or seed varieties, I’ll start losing a lot of my potential for a quality crop,” says Sayle, who grows row crops on 1,500 acres in northwestern Mississippi. “If I take out agricultural practices, such as burndown and residuals, I could potentially get in over my head quickly with these weeds. And then I’ll go from spending $5 to spending $25 to try to catch back up with a post.”

For years, Sayle has relied on the residual of Valor Herbicide in a variety of capacities, including spring pre-plant applications. In recent seasons, he’s added Fierce Herbicide into the mix.

Sayle tries to spray within 48 hours of planting—the first of many steps to combat pigweed, which is a constant struggle in his fields.

“With those weeds, if you get behind a day or two, it can be the difference between a clean crop and a filthy crop,” he says. “Putting Valor down can help provide a good blanket of security at holding them back.”

Not all fields treated equal

Having a plan in place like Sayle’s and not making applications on the fly will continue to be the key to a successful soybean crop this year, says Frank Carey, product development manager for Valent U.S.A. Corp., the maker of Valor and Valor XLT soybean herbicides, and Fierce and Fierce XLT soybean herbicides. Carey advises growers to plan a chemical budget on a field-by-field basis.

“On a field with little weed pressure, I may use Valor or Valor XLT, and on another with high weed pressure and known resistance, I may need a longer residual, so I will use Fierce or Fierce XLT,” he says. “Growers need to look at each individual scenario and make the best management decision for that field.”

Another factor in spring weed management programs is pent-up moisture and humidity. The warm weather that closed out 2015, coupled with the flooding many areas experienced at the beginning of 2016, could have moved weed seed from one field to another and sped up germination.

Growers also should be on the lookout for large-seeded weeds, such as common cocklebur and sicklepod, which are making a comeback this year.

A “boots on the ground” approach helps inform growers of their weed situation and allows them to be timely in their applications.

“One of my favorite sayings is, ‘Cleanliness is next to godliness.’ But when it comes to pigweed control, ‘Timeliness is next to cleanliness,’” Carey says. “Timely applications and proper calibration are going to be especially important this year.”

Above all, mix it up

Bob Scott, weed scientist with the University of Arkansas, recently said this about weed management, “If everything is working great, change it!”

Carey echoes that sentiment, adding that the best way to combat or prevent resistance is to use multiple effective modes of action (MOAs).

“It’s important to make sure that we’re not overusing a particular singular MOA and relying on just one thing,” he says. “We’re trying to be proactive in our approach. If you keep doing the same old thing, it’s going to come back and bite you. Mother nature will find a way around it.”

For Sayle, cultural practices, such as crop rotation, work in tandem with using “different chemistries involved on different acres over the years, to try to keep the weeds guessing.”

Valent U.S.A. Corp. contributed this article.

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