We first heard about Olympus, a new herbicide from Bayer CropScience, in 2000. But it has taken until 2004 for the EPA to register the herbicide for wheat growers. It's worth the wait: Olympus promises good postemergence control of cheatgrass, downy brome and Japanese bromegrass, without crop rotation restrictions that plague competitive herbicides.
"We are confident, based on a number of years of research, that Olympus will control winter annual brome grasses, particularly cheat," explains Phil Stahlman, Research and Extension weed specialist at the Kansas State University Agricultural Research Center in Hays. Olympus offers the flexibility of a fall or spring application, but control is most effective when the herbicide is applied in the fall, Stahlman adds.
Olympus contains the new active ingredient, propoxycarbazone-sodium, which is a key characteristic of this herbicide.
"It has similar activity to a sulfonyurea herbicide, but is a completely new class," Stahlman explains. "That is a major advantage. The rotation restrictions are considerably less than competitive herbicides."
With competing herbicides, the crop rotation interval was at least 24 months. Although the Olympus label has not yet been made public, you should be able to plant grain sorghum and corn the spring after harvesting wheat without crop injury.
Use-rate of Olympus is 0.6 to 0.9 ounces per acre in a single application. Apply the herbicide when weeds are actively growing and wheat has emerged, but before jointing. You may follow a fall application of Olympus with a spring application up to 1.2 ounces per acre. Olympus can be tankmixed with many broadleaf herbicides for one-pass control of troublesome weeds.
Bayer CropScience advertises that Olympus is effective on jointed goatgrass, but Stahlman believes Olympus will suppress, rather than control, this obnoxious grass weed. "It may reduce the competitiveness of jointed goatgrass and reduce seed production, but control has been inconsistent," he says.
Bayer CropScience claims it is one of a few crop protection companies to invest in herbicides for the cereal grains market. "Olympus herbicide is just one of several new products Bayer CropScience is developing for cereal growers," says Dave Feist, product manager with Bayer CropScience.
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