Lower future prices and a recurring basis problem at Mid-South and Southeast grain elevators may have taken some of the luster off soft red winter wheat. But wheat farmers may have at least one bright spot this season with the addition of a new herbicide to their arsenal.
EPA has granted Dow AgroSciences a Section 3 registration for its PowerFlex herbicide. PowerFlex contains a new active ingredient, pyroxsulam, that promises to help control Italian ryegrass, cheat, henbit, chickweed, Carolina geranium and various mustard species when the spring herbicide spraying season rolls around.
“Pyroxsulam was first synthesized by Dow AgroSciences in 1998,” said Hub Miller, product launch specialist for the company. “It's been in various stages of testing since then and was approved by the EPA earlier this year. We think it will offer growers a number of advantages throughout the wheat-growing regions of the United States.”
Miller, a speaker at a consultants' conference sponsored by Dow AgroSciences in Memphis, Tenn., says PowerFlex offers producers an opportunity to address several weed control problems with one product.
Given the increasing production costs associated with wheat and other crops, that could be important in 2009, says an area Extension grains agronomist.
“Because of the weed control spectrum of PowerFlex, growers can use one herbicide to control the majority of weed species present in Mid-South wheat, instead of one herbicide for ryegrass control and another for broadleaf control,” says Mississippi State University's Erick Larson.
“In addition, the rotational flexibility of PowerFlex gives growers cropping possibilities. We really don't have another herbicide that has a combination of cropping flexibility and broad-spectrum weed control like PowerFlex does.”
Miller says PowerFlex, which will be sold as a wettable granule, will have a standard use rate of 3.5 ounces per acre. It can be applied postemergence on wheat ranging from three-leaf to jointing in the fall or spring.
“We've seen our best control when grasses are in the two-leaf to two-tiller stage and broadleaf weeds before they are 2 inches in height or 2 inches in diameter,” he notes. “Weeds should be actively growing. Drought conditions or temperatures near or below freezing may reduce weed control and increase the risk of crop injury.”
Some tests in the Mid-South have shown that PowerFlex can provide 99 percent control of Italian ryegrass in wheat that produced an average yield of 63 bushels per acre. Researchers have observed similar levels of control for henbit and annual bluegrass.
“We usually see what's called a green death with PowerFlex,” says Miller. “In general, target weeds are slower to die with PowerFlex, but the end result is the same.”
PowerFlex offers growers improved crop rotation flexibility versus most other winter wheat herbicides. For example, it contains a short nine-month interval for rotating into crops like soybeans, sorghum, peas, lentils, sugar beets, corn, potatoes, canola and sunflowers in all geographies.
Even shorter intervals for certain crops will be allowed in specific geographies.
“Through an innovative new molecule, PowerFlex brings a new standard of performance for grass and weed control in winter wheat and will be a critical component for growers to achieve effective weed control in winter wheat,” says Monte Weimer, product technology specialist for Dow AgroSciences.