2/16/2021

Flexible Weed Control Is Crucial for PNW Wheat Farmers

Match herbicides to field environment

In a state where microclimates are common, agronomist Sam Kimmell has learned to tailor his weed control recommendations for wheat to fit varied production environments and a wide range of soil moisture conditions.

Kimmell, with The McGregor Company in Endicott, Washington, covers a territory that includes diverse microclimates influenced by the Pacific Ocean, mountain ranges and area lakes. His grower-customers experience annual rainfall amounts ranging from 7 inches to 32 inches, with the bulk of all rain falling between October and February. That wide variation impacts weed spectrum, crop rotation and production budgets.

On the west end of his territory, wheat farmers must find ways to compensate for low annual rainfall, while battling Russian thistle, pigweed and marestail. Those farmers are more likely to be operating on a reduced crop production budget due to a lower yield potential.

In comparison, those areas with high rainfall totals point to kochia, prickly lettuce and marestail as their biggest weed issues.

Further complicating matters is an increase in documented Group 2 resistance, particularly to marestail and grassy weeds such as Italian ryegrass.

“No Group 2 herbicide will touch Italian ryegrass in our higher rainfall areas. We can often control it with Group 15 herbicides in winter wheat, but not in spring wheat,” he says. “We have had to plant many acres to spring canola due to Group 2-resistant Italian ryegrass. Those acres get put back into wheat and Quelex has been a go-to with the addition of a pyroxsulam (PowerFlex HL or OpenSky) to help control the volunteer canola that comes though.”

“On our chemical fallow acres we have been using Quelex to control the onset of marestail and have seen tremendous results,” he adds.

Quelex® herbicide also provides the rotational flexibility that other tank-mix partners do not offer. “Quelex gives us plant-back ability for brassicas,” he says.

Most of Kimmell’s growers are on a three-year crop rotation, rotating either between winter wheat, spring wheat and chem fallow or winter wheat, spring wheat and legumes.

Winter wheat is where the portfolio of herbicides from Corteva Agriscience shines, he says.

“Winter wheat is our baby. We put more inputs into that with average yields of 100 bushels and a yield range from 60 to 180 bushels per acre, depending on the year and rainfall,” Kimmell adds.

In 2020, Kimmell put WideARmatch herbicide to the test on a grower’s dryland winter wheat acreage that received 16 inches of rainfall. WideARmatch was applied the third week of April at the recommended labeled rate.

“We put it in a spot where we have issues with mayweed and rush skeletonweed, and it did really well,” he says.

Kimmell also appreciates the convenience of multiple product sizes Corteva offers for WideARmatch.

“It’s convenient. Many of my larger growers won’t buy a product if it doesn’t come in a tote,” Kimmell says.

OpenSky® , PowerFlex HL® , Quelex® and WideARmatch are not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.