Weed Cures

May 15, 2009 02:05 PM

Say Bayer and most people think aspirin. For farmers, the company increasingly represents a cure for weed headaches.

During the past 10 years, Bayer CropScience has been launching two to three active ingredients per year, says Friedrich Berschauer, chairman of the board. Insecticides, fungicides and seed treatments are valuable members of the Bayer product mix, but dig deep and you'll find it is herbicides that are currently driving discovery.

A decade of glyphosate dominance is leading to a reckoning as resistance to the popular herbicide spreads. Even Monsanto Company is recommending farmers add a soil-applied residual to its Roundup Ready program. Add acetolactate synthase (ALS) and proto- porphyrinogen oxidase (PPO) resistance to the scenario and the need for new products and new modes of action has never been greater.

This past March, two dozen leading U.S. weed scientists and Farm Journal toured Bayer's headquarters for herbicide discovery in Monheim and Frankfurt, Germany. What we found among the acres of greenhouses is a company aggressively pursing traditional herbicide chemistry.

"That's good news for farmers who desperately need new modes of action,” says University of Illinois weed scientist Aaron Hager. "Weed resistance is enough of an issue that most farmers now realize the dangers of overreliance on one product.

"It's impressive to see a company still screening so many compounds in a year. Thirty years ago, nearly all manufacturers were doing this. This gives hope that there will be new and inventive chemistry that will find its way into the marketplace,” Hager says.

Discovery challenges.
Hansjoerg Kraehmer, Bayer's head of herbicide profiling and support in Frankfurt, says bringing a new active ingredient to market is no small task. "They used to call what we do blue sky chemistry,” Kraehmer says. "Each year we test 200,000 to 400,000 compounds. Gene expression profiling with DNA microarrays is one technology that makes our jobs easier, but still, only 100 of those compounds will make it to field testing and from those, only one is likely to survive to reach the farmer's field,” he says.

He points to the declining number of crop protection patents as proof of the challenge. In 1990, some 250 new compounds were patented worldwide. This year, he estimates, 50 herbicide patents will be filed. Many old patents are also being withdrawn. Companies must take care that they do not take too long coming to market or they risk running too close to patent expiration to justify commercialization.

There's no question that the success of glyphosate has and continues to influence the market. "It is a remarkable product with 300,000 tons produced annually worldwide,” Kraehmer says. "From our point of view, it is a cheap molecule to make and we must compete with that,” he says.

"The standards are high—new pesticides usually contain highly effective molecules with more complex structures. We must also try to protect as many plants as possible with as little active ingredient as possible—all the while making it safe for the farmer and the environment. Then, it must be produced at a price that is cheap enough to be attractive to the farmer and cost-effective enough for us to pay back our investment,” he explains.

New ingredients trickle through the pipeline, but new modes of action are a different matter. "Farmers may not realize there hasn't been a new [herbicide] mode of action discovered since 1985,” Kraehmer adds. "We are looking very hard, but I fear most targets in the plant have been exploited.”

New products. Bayer ranks No. 3 in the global herbicide market. Growers are familiar with Puma (fenoxaprop), Liberty/Ignite (glufosinate), Buctril (bromoxynil) and Balance (isoxaflutole). Three actives have recently come out of the pipeline: pyrasulfotole, (Huskie) and tembotrione (Laudis), both HPPD inhibitors, and thiencarbazone-methyl, an ALS-inhibitor.

Bayer CropScience's portfolio is expanding with new products as proprietary safener technology confers crop tolerance.

A new formulation of Balance Flexx debuted this year with a new safener (cyprosulfamide) to boost crop safety. Corvus, a two-mode-of-action product, teams Balance Flexx and the new ALS-inhibitor with the cyprosulfamide safener. For 2010, farmers can expect to see Capreno approved for use. It combines two active ingredients (tembotrione and thiencarbazone-methyl) with a safener (isoxadifen) to deliver a new postemergence option.

Brent Philbrook, Bayer CropScience herbicide product development specialist, says the company strives to offer flexibility so growers can fine-tune and customize. "In the next 10 years, half of the row-crop area in the U.S. will have weed populations that can't be managed with glyphosate alone,” he says.

"In spite of the value shift to transgenic crop herbicide markets, a con-siderable market for conventional herbicide chemistry will remain as complimentary chemistry to glyphosate gains importance,” Philbrook adds.

Bayer is well vested in traits, too. LibertyLink corn, cotton and canola already had a foothold, but this year Bayer rolled out LibertyLink soybeans after a decade-long push to gain foreign market clearances.

"We have struggled, fought and clawed to bring this technology to market,” says Rob Schrick, corn/soybean seeds, traits and herbicide product specialist for Bayer. "The primary thing we want to communicate is we are committed to another trait platform. Anytime a new option is introduced, the farmer wins.”

Bayer's GlyTol, a glyphosate-tolerant cotton, hit the market this year. By 2014, the company expects to have a second-generation trait system for soybeans stacking LibertyLink with GlyTol and HPPD-tolerant (Balance) traits.

Farmers might be surprised to learn the company has more than 120 years of experience in crop protection, notes Michael Deall, vice president of marketing and portfolio management. "Over the next five years, Bayer CropScience plans to invest $4.8 billion in research and development—$3.7 billion in chemistry and $1.1 billion in biotechnology,” Deall says.

Technology Makes Herbicide Safer for Crops

Most everyone understands how the LibertyLink and Roundup Ready programs work. The seeds produce genetically altered plants that resist the corresponding herbicide. Now, Bayer CropScience is offering new herbicide innovations that are not trait-specific. So how can herbicides kill weeds while sparing the crop?

The secret is in the safener technology. Safeners are specific additives included in the herbicide formulation or added to a seed treatment that reduces a crop's response to an herbicide.

University of Nebraska weed specialist Mark Bernards says safener technology exploits subtle differences between enzyme systems of crop plants and weeds. Put simply, the safener allows the crop to metabolize the herbicide fast enough to avoid injury but doesn't confer the same benefit to the weed.

"Herbicide safeners were introduced commercially in the 1970s to protect corn from injury caused by EPTC [Eptam or Eradicane]. Later safeners like Concept were developed to protect sorghum from injury caused by Dual,” Bernards says. "Since then, safeners have been used with many different herbicides in cereal crops. Bayer recently commercialized two new safeners that will expand the usefulness of this type of technology.”

Bayer's latest safener technology is trademarked CSI (Crop Safety Innovation) and is proprietary and, so far, specific to corn herbicides. Other cereal safeners are in the pipeline, and the search is on for compounds to protect dicot crops.

"The cool thing with safeners is they may allow companies to re-evaluate herbicides that were not developed because they caused injury to the crop,” Bernards adds.

You can e-mail Pam Smith at psmith@farmjournal.com.


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