Weeds wait. An estimated 50 million to 300 million weed seeds lie buried below each acre of U.S. cropland. Of the 250,000 plants species that occur throughout the world, about 1,000 are recognized as weeds and 76 are considered vile enough to be labeled as the worst weeds. Weed control has been, and likely always will be, one of the most challenging aspects of profitable crop production.
Somewhere along the path to efficiency we lost sight of that fact, says Daniel Stephenson, Louisiana State University Ag Center weed scientist. "The convenience, ease, cost and effectiveness of the glyphosate system lulled a whole generation of farmers into thinking it was foolproof," he says.
Back to the basics. The challenge now is to find weed management programs that preserve glyphosate technology in a way that is practical. "Glyphosate-resistant crops allowed our growers to grow their farms too," Stephenson says. "Our growers are going back to school when it comes to weed identification, application and timing."
The weed spectrum has changed during the past decade and a half, says Bill Johnson, Purdue University weed scientist. "Prior to glyphosate technology, three of the top 10 weeds would have been grasses. Today, Roundup Ready volunteer corn is our only real grass problem in Indiana," he says. "Annual broadleaf weeds are by far the most prolific weeds."
The key to this new weed era is giving the advantage back to your crop, says Dick Oliver, University of Arkansas weed scientist. "Farmers need to focus less on what chemical will control the weed and more on the basic weed ecology and biology," he explains.
"The most important part of a weed control program today is to know the weed, how the weed grows and when you can and can’t manage it," Oliver says.
- Early Spring 2011