MONSANTO IS cutting the price on its Roundup brand agricultural herbicides. “We will be reducing the price of Roundup PowerMax and Roundup WeatherMax by up to 50%, effective immediately,” says Matt Helms, marketing manager for Monsanto crop protection division.

Global supply-and-demand issues put glyphosate prices on a roller coaster ride recently, with prices falling dramatically from 2008 and 2009 levels back down to 2006 and 2007 levels.

Chris Boerboom, extension weed scientist at the University of Wisconsin, says producers should continue to be aware that the use of preemergence herbicides in a corn and soybean rotation may still be necessary. “The addition of a preemergence herbicide has been shown to decrease early season weed pressure, which is especially valuable in fields when weather delays postemergence glyphosate applications,” he says. “And controlling early season competition protects yield.”

The price of glyphosate won't matter if there are glyphosate-resistant biotypes in your field, says Aaron Hager, weed science extension specialist at the University of Illinois. “Certainly producers may look at spraying glyphosate twice instead of using a soil-residual herbicide,” he says. “But alternating chemistries is imperative, especially if glyphosate resistance is a concern.”

Joe Sandbrink, technology development manager for Monsanto crop protection division, encourages the use of residuals in tankmixes when needed. “Our Roundup Rewards program provides incentives to producers who use other chemistries in areas where multiple modes of action are necessary for weed control,” he says.

Monsanto's price cut isn't likely to spill over into other weed-control chemistries. “We don't expect current glyphosate prices to directly impact other chemistries, as the prices of these products did not spike like glyphosate,” says Scott Langkamp, head, herbicide brand management, Syngenta Crop Protection.