It wasn't that long ago that residual herbicides were being given up for dead as farmers flocked to glyphosate-resistant crops of cotton, corn and soybeans because of the ease of application and relatively low herbicide costs.

But the discovery of glyphosate-tolerant and -resistant weeds such as horseweed and Palmer amaranth and the rising cost of glyphosate are prompting companies to bring new residual products to the marketplace.

One of the latest is saflufenacil, a residual herbicide BASF expects to register as Kixor in 2010. Kixor can be used alone or mixed with glyphosate and applied preplant for “fast and complete” burndown of more than 80 dicot weeds, including those resistant to glyphosate and ALS herbicides.

“We are really excited about Kixor,” said Peter Eckes, head of crop protection research and development at BASF's Crop Protection Division. “Kixor is another product of our strategy of focusing on innovation.”

Eckes said BASF believes Kixor has “blockbuster potential” when it comes to market year after next if EPA gives its blessing. BASF's anticipated launch, possibly for the 2010 growing season, comes at a time when farmers are seeking more help with glyphosate-resistant weeds.

“Our customers need novel chemistry, particularly in light of increasing resistance to popular herbicides such as glyphosate,” he said, speaking at a media summit, ‘Innovate 08,’ held by BASF in Washington, D.C.

Kixor can be used as a pre-emergence treatment in corn and sorghum to control all major dicot or broadleaf weeds without triazine herbicides. BASF also plans to market products with Kixor for burndown and residual control of dicot weeds in non-crop segments.

The Kixor active ingredient is a PPO inhibitor that features a new mode of action. Its primary targets are broadleaves, including weeds like giant ragweed and horseweed that have become resistant in some cases to glyphosate, triazines, and ALS inhibitors. Kixor will have no crop rotational restrictions and can be used on 30 crops.

“The product delivers fast broadleaf burndown, has good overall residual activity in the soil, and gives season-long broadleaf control,” says Eckes. Kixor also has excellent crop safety, he notes.

In corn and sorghum, Kixor will be applied pre-emergence. It will be a preplant burndown product in soybeans, cereals, cotton, and legumes. It can be used alone or in combinations with glyphosate in the preplant burndown option.

Despite its attributes, Kixor could have been a missed opportunity for BASF and farmers. The company actually considered dropping its herbicide program after Roundup Ready crops took the agricultural stage by storm.

“At one point, we asked ourselves if we should exit herbicide research,” said Michael Heinz, president of BASF Crop Protection. “But we knew if we did that, it would take a long time to get back in the game. I believed we would see a renaissance of herbicides due to constant use of glyphosate after glyphosate after glyphosate.”

“Glyphosate is not bulletproof anymore,” said Markus Heldt, group vice-president for BASF's North American crop protection division, referring to the weeds no longer controlled by the herbicide. “Kixor will bring faster, sharper broadleaf control to the market.”

BASF plans to offer Kixor stand-alone and in combination with its imidazolinone herbicides and other products. Including Kixor, BASF has five active ingredients and one herbicide tolerance project in its development pipeline.