There’s a long string of newer herbicide modes of action in the works.

Bayer expects to release added LibertyLink herbicide traits in beans in about 2013, according to the ASA industry pipeline chart (see chart).

With the need for more residual herbicides, Syngenta and Bayer are co-developing an HPPD herbicide-tolerant trait for soybeans, says Quinn Showalter, Syngenta commercial traits product leader. “The trait is in early development, with launch in North America expected in the second half of this decade,” Showalter says.

“The HPPD trait will be an important new tool for increasing pressure from resistant and hard-to-control weeds,” he says.

Two weed scientists explain the significance of this technology: “Any pending technology to utilize HPPD inhibitors in soybeans – which have been around in corn for some time – would provide another tool to control glyhosate-resistant horseweed, waterhemp and pigweed in soybeans,” says Purdue Weed Specialist Glenn Nice. “Dual resistance among some of these weeds is starting to dwindle our options in soybeans.”

Bryan Young, Southern Illinois University weed scientist, adds, “Some of the HPPD-inhibiting herbicides such as Balance and Callisto provide foliar and soil residual weed activity (in corn).  (If developed for soybeans) the addition of a herbicide with both foliar and soil activity would be a welcomed addition to soybean production and the current use of glyphosate. Residual herbicides are a critical component in building a diverse, robust chemical weed-management strategy.

“The HPPD herbicides also have greater activity on broadleaf weeds than grass weeds. Since most of the glyphosate-resistant weeds that have developed are broadleaf species, this mode of action would likely complement glyphosate well,” Young says.

Ready for release in about the same mid-decade time span are much-anticipated dicamba-tolerant varieties from Monsanto, “which will be stacked with the higher yield potential of Genuity Roundup Ready 2 Yield trait technology,” Monsanto’s Fuchs says.

The addition of the dicamba-tolerant trait to the Genuity Roundup Ready 2 Yield trait technology will add tolerance to two herbicides with two different modes of action for new weed-control options for many tough-to-control broadleaf weeds, he says.

The stack will enable dicamba and glyphosate herbicide use for preplant burndown with no plant-back restrictions at planting, and for in-season weed control. “This will complement the flexible and effective Roundup Ready and Roundup Ready Plus weed-management systems that control hundreds of weeds,” Fuchs says.

Good season-long weed control is projected from the new Pioneer technology Optimum GAT. It’s designed to provide more flexible use of glyphosate and selected ALS herbicides without risk of crop injury.

“We believe that a holistic approach, encompassing new technologies, management techniques and open communication and education with Pioneer growers, is needed to address concerns of weed resistance,” Pioneer’s Iwig says.

Dow AgroSciences will offer a new herbicide-tolerant trait technology called the Enlist Weed Control System. It will provide robust tolerance to a new 2,4-D product and will be stacked with the glyphosate-tolerant trait. Pending regulatory approvals, the trait will be available in soybeans for the 2015 crop year.

“The Enlist system will offer multiple modes of action against hard-to-control and resistant weeds, while allowing growers to continue to farm the way they prefer,” says Damon Palmer, Dow AgroSciences U.S. commercial leader. Enlist will provide growers a very effective tool, as they face a very real threat to productivity, he says.

Pioneer is also licensing the Enlist technology and incorporating it into Pioneer genetics. “Growers are losing a fair amount of yield to glyphosate-resistant and hard-to-control weeds,” says Iwig. “To offer a solution will bring a step change in value to growers.”