In a perfect year, weed control in the Pacific Northwest’s winter wheat crop kicks off with a fall herbicide spray. Most years, however, don’t bring perfect weather, necessitating spring weed control treatments.
“Four out of every 10 years, our wheat is out of the ground before the snow hits. Two out of every 10 years, we get heavy early season weed growth and ideal weather that enables us to make a fall spray. In most years, we are controlling weeds in the spring,” says Jason Johnston with McGregor Co. in Plaza, Washington.
Annual weeds, especially fall-germinating species, may be more difficult to control after a springtime temperature boost.
“It’s more difficult to effectively control weeds coming out of winter. Plants develop a toughness. They’ve survived winter and have hardened off and have a jump on size come spring,” Johnston says. “By the time we can spray with herbicides, our problem weeds are often oversized."
"When annual grasses get size to them, they are especially difficult to control.” — Jason Johnston
Among the winter annual grasses Johnston is targeting are cheatgrass, downy brome and dogfennel. Other problem weeds are prickly lettuce, mustard species and Italian ryegrass.
“In our no-till wheat, an especially troublesome weed is rattail fescue, which doesn’t like tillage. Another huge problem for no-till producers is wild oats,” Johnston says.
Wheat yield potential and weed spectrum drive Johnston’s herbicide recommendations.
“Our decision-makers are dogfennel and downy brome. They are tough to kill, and we have limited effective chemistries,” he says. “One of the best herbicides for dogfennel control is WideMatch. We also use a lot of Starane Flex herbicide in a tank mix.”
Ideally, Johnston advises his wheat growers to begin spraying with WideMatch® herbicide in the spring, as soon as nighttime temperatures are forecast to remain above freezing.
“If you’ve got dogfennel in the mix, there’s no comparison between Huskie and WideMatch,” he says. “WideMatch gives a better kill on dogfennel and bigger weeds than competing treatments. It also does really well on Canada thistle and will pick up some mustards.”
Now that WideARmatch® herbicide is available, Johnston predicts that most sprays of WideMatch® herbicide in his area will convert to WideARmatch herbicide.
Starane® Flex, WideARmatch® and WideMatch® 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.
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