OMAHA (DTN) -- The 2010 corn season has only a few truly new herbicides for growers. Mark Loux, weed scientist at Ohio State University, said, while it may be a slow year for new active ingredients, “there are still a lot of good herbicides available on the corn side.”

Another wet spring could put more emphasis on postemergence weed control. (DTN photo by Greg Horstmeier)

"Bayer and BASF are the only companies that still have big (active ingredient) discovery programs. We just aren't going to see much new other than new generic formulations and premixes." The good news, he added, is those generics and mixes typically mean more competition and lower prices.

One of those old-timers, atrazine, has an uncertain future beyond 2010. The Environmental Protection Agency is taking another look at its fate, due to concerns over human health and aquatic wildlife issues.

"Atrazine makes everything work well and even a quarter pound will really improve control,” Loux said. “We can farm corn without it, but it will raise the cost of weed control."

Estimates are that 75 to 85 percent of corn planted is herbicide tolerant and resistant to glyphosate (Roundup and generic) products and glufosinate (Ignite) products. Planting those hybrids dictates what herbicides are applied. In the future, more herbicide-tolerant traits -- conferring resistance to 2,4-D, dicamba and ALS (acetolactate synthase) herbicides -- will be marketed.

SAFLUFENACIL

BASF is bringing its Kixor family of herbicides to commercial market. Kixor products are based on the active ingredient saflufenacil, which is a broad-spectrum, broadleaf herbicide. Formulations for corn include the brands Integrity and Sharpen.

Brady Kappler, BASF tech service representative, said saflufenacil controls more than 70 broadleaf weeds. It is targeted as a burndown agent that also gives residual control. He said when it's added to glyphosate, it seems to "speed up grass kill."

Integrity is a premix of dimethenamid (Outlook) and saflufenacil and is labeled for preplanting and pre-emergence use on corn and soybeans. Dimethenamid controls grasses and small-seeded broadleaf weeds, such as waterhemp, pigweed and nightshade. Adding saflufenacil expands broadleaf control, Kappler said.

Loux tested Integrity at rates as high as 20 ounces per acre, which provided residual broadleaf weed control comparable to or better than competitive standards such as atrazine premixes, seen in Lexar/Lumax. “However, similar to the approach that Dow has taken with SureStart, Integrity is labeled for use only in pre-emerge followed by postemergence herbicide programs."

"Integrity stacks up better than the old standards of acetochlor plus atrazine," Kappler said. "It's better on velvetleaf, lambsquarters, cocklebur, sunflower and waterhemp." What sets it apart, he said, is the fact that they are not using atrazine in corn. Integrity requires lower use rates and less handling. "We see it as displacing atrazine."

BASF is marketing Integrity as a fit into the Roundup Ready system as a two-pass program. Kappler said it will work equally well in conventional (non-Roundup Ready) corn, but growers need to have a good postemergence package.

Sharpen, which contains only saflufenacil, has both residual and postemergence activity on emerged weeds. As a replacement for 2,4-D, Loux feels it's inadequate. "Our research shows that while Sharpen applied alone has some foliar activity, it will not adequately control emerged weeds in no-till fields unless mixed with another herbicide that has effective foliar activity (glyphosate, Ignite). It is likely to contribute more activity on annual weeds than on biennials or perennials."

Loux attributes this to saflufenacil being a contact herbicide that doesn't translocate like 2,4-D. To control winter annuals, he believes farmers need a herbicide such as 2,4-D, glyphosate or chlorimuron.

THIENCARBAZONE-METHYL

Thiencarbazone-methyl is an ALS-inhibiting grass herbicide that has residual and foliar activity and works by suppressing the plant's metabolism. That gives it both pre-emergence and postemergence grass control. Bayer released thiencarbazone-methyl, the active ingredient in Corvus and Capreno brands, following a limited launch of Corvus in 2009 in the Eastern Corn Belt.

Corvus contains thiencarbazone with the safener cyprosulfamide and isoxaflutole (Balance Pro). It is intended for the one-pass, full-season weed-control market. In corn, it can be applied up to V2 leaf stage.

Loux said Corvus provides broad-spectrum residual control of grass and broadleaf weeds when applied pre-emergence. Adding atrazine will improve control of large-seeded broadleaf weeds such as giant ragweed, cocklebur and morning glory. It also will improve control of emerged weeds in a burndown or postemergence application.

Capreno contains thiencarbazone-methyl and tembotrione (Laudis). Capreno is labeled for postemergence use in corn and provides broad spectrum control of a variety of grass and broadleaf weeds.

It can be applied from V1 to V7 leaf stage. Loux said it is most effective when broadleaf weeds are less than 6 inches tall and grasses are less than 3 inches tall. He said adding atrazine can improve control.

OTHER HERBICIDES UPDATES

Balance Flexx from Bayer is a new formulation of isoxalutole that contains cyprosulfamide to reduce risk of corn injury. It replaces Balance Pro.

Callisto Xtra is a new premix from Syngenta that contains Callisto (mesotrione) and atrazine and is labeled for postemergence applications.

Prequel is a new premix from DuPont that contains rimsulfuron (Resolve) and isoxaflutole (Balance). This product is for a pre-emergence and postemergence program. Weed control is improved with atrazine.

SteadFast Q and Accent Q arenew formulations from DuPont that contain a safener, isoxadifen, to reduce the risk of corn injury. They replace Steadfast and Accent.

Daniel Davidson can be reached at daniel.davidson@telventdtn.com

(GH/ES/KM/SK)

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