James Wray is overlapping residual herbicides to keep pigweed under control in his soybeans

James Wray is overlapping residual herbicides to keep pigweed under control in his soybeans.

Overlapping residuals helping keep pigweed at bay

The Wrays had been applying Dual as a residual/postemergence herbicide in their cotton for a number of years, but James Wray decided to apply Warrant (acetochlor) on their cotton in 2015  “to change the chemistry from what we had been applying, and it turned out well."

James Wray is searching for something he’d rather not find as he combs one of the fields of soybeans he and his father, Eddie Wray, are growing on their farm near Payneway in northeast Arkansas.

The younger Wray is looking for Palmer amaranth or pigweed, a weed described by University of Arkansas Extension scientists as the state’s No. 1 weed problem, as he hosts a group of visitors to the farm in late May.

He was interviewed about his use of residual herbicides on the cotton, corn, rice and soybean farm where Wray is overlapping those pre-emergence herbicide applications to try to keep pigweed under control. When he finally finds a pigweed, it’s on the edge of the field next to his last rows.

“This is an old one,” he says. “It already has a seed head although it’s small. I don’t think my sprayer guy hit these outside rows.”

When you first talk with James Wray, you might get the impression he’s been farming for years. He discusses variety selection, herbicide programs, irrigation and crop monitoring like a veteran producer.

2014 graduate of ASU

Then you learn he graduated from Arkansas State University with a degree in civil engineering in May of 2014, which means he just finished planting his second crop after leaving college. But Wray’s on-farm experience goes back a ways.

“I was driving a tractor when I was 11 or 12,” he says, “And I was pulling a planter by the time I was 12 or 13. I worked on the farm all the way through high school, and I’d come home from class in Jonesboro in the afternoons and help my Dad (Eddie Wray) on weekends when I was attending ASU.”

Wray’s grandfather, J.E. Wray, came to northeast Arkansas with his family from Montgomery County, Miss., in 1935. In 1939, the family moved to Payneway, which is located about 40 miles northwest of Memphis. Generations of the Wray family have been farming there ever since.

 “For years we grew mostly cotton,” said James. “Then, in 2011, we decided to plant more corn and soybeans because of the higher grain prices. We were fortunate because that turned out to be a bad year for cotton here.”

Last year was a transition year as James got into farming fulltime. This year his father has turned over more of the decisionmaking on tasks such as variety selection and controlling weeds in the crops they grow.

PPO resistance a growing concern

Pigweed has become a major problem in this area because of, first, glyphosate- and now PPO-resistance and because the weeds produce millions of seed that can germinate at any time during the long growing season.

“We’re trying to overlap our residuals so we can control these pigweeds,” he said. “We come behind the planter with 3.5 ounces of Envive, and, while that Valor is still holding, get some Warrant out to keep the residual there so that when we get to canopy we can have a clean field and not have to worry about the pigweed pressure.” (Envive is a mix of Classic, Valor and Harmony herbicides.)

The field was planted with Asgrow 4632 Roundup Ready 2 Yield soybeans on April 6. Most of the field was weed-free on May 23 (when Wray was interviewed) except for a few sprigs of scattered ryegrass that he planned to control with Roundup herbicide prior to canopy.

“The concern in Arkansas and our No. 1 weed is pigweed,” says Tom Barber, Extension weed scientist with the University of Arkansas System Division of Agriculture. “Controlling pigweed or Palmer amaranth starts early with a clean field and a residual herbicide at planting.

“I believe he said he used Envive on this field, which is a good option,” said Dr. Barber, who looked at several fields on the farm. “It has Valor in it, which has good activity on pigweed, and he’s come back with Warrant Ultra. So that’s overlapping residuals before pigweed emergence.

Recommended practice in Arkansas

We just walked the field, and we didn’t see many pigweed in the field.”

He said the Wray’s approach provides overlapping residuals and two modes of action working against the pigweed in the field, two critical ingredients in preventing the further development of herbicide resistance in the problem weed.

“Our concern moving forward with PPO resistance being fairly widespread through this part of Arkansas is what we’re going to get from the Valor component early if we do have PPO-resistant pigweed present in the field,” he noted. “We’re doing further research to determine what our best products are going to be in that situation.”

“In this field for now, the Valor is still working; we’re using Warrant Ultra over-the-top; and overlapping the residuals, which is what our recommendation is for soybean production in Arkansas.”

It’s been another “typical” spring in northeast Arkansas. Some of the Wray’s corn received six-inch rains – on two occasions. The soybeans received one of those six-inch downpours, but the excess moisture did not appear to have reduced the effectiveness of the residual herbicide application at planting.

The Wrays had been applying Dual as a residual/postemergence herbicide in their cotton for a number of years, but James Wray decided to apply Warrant (acetochlor) on their cotton in 2015  “to change the chemistry from what we had been applying, and it turned out well.

“I wanted to try Warrant with Flexstar (fomesafen) last year, but it was difficult to tank-mix the two products when you’re covering as much ground as we are at this time of year,” said James. (The Wrays farm about 5,000 acres of owned and rented land.)

“Then Ty (Mason, his local Helena field representative) told me they were coming out with a pre-mix of Warrant and Flexstar that would be called Warrant Ultra. We like the Warrant Ultra because the fomesafen provides immediate postemergence control and the micro-encapsulated formula for Warrant helps provide longer residual control.”

They applied 50 ounces of Warrant Ultra and 32 ounces of Roundup on the Roundup Ready soybeans.

Wray says he and his father have also observed less herbicide “burn” with Warrant Ultra than some of the other early postemergence products that are available.

What’s next for the soybeans?

“Pretty much just watering it,” says Wray. “We’lll keep an eye on it and around R3 we’ll spray a fungicide and Co-R-on, like a 10-0-10 or something like that. Then we’ll move on to harvest.”

For more information on residual herbicides, visit https://www.uaex.edu/publications/pdf/mp44/mp44.pdf

TAGS: Cotton Weeds
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