Linda Benedict, Schultz, Bruce | 2/25/2011 10:25:49 PM
Farmers from across the Midsouth, along with researchers from the LSU AgCenter and several other universities, met Feb. 1-2, 2011, to share techniques and ideas at the National Conservation Cotton and Rice Conference.
Much of the 14th annual conference concentrated on herbicide-resistant weeds. LSU AgCenter researchers confirmed the presence of herbicide-resistant pigweed in two north Louisiana parishes recently. Last year, resistant pigweed and johnsongrass were confirmed in Louisiana.
LSU AgCenter weed scientist Daniel Stephenson was among the 54 researchers to present results of their work. Stephenson advised farmers to use herbicides with varying modes of action, and that means glyphosate with 2,4-D or dicamba and not relying on glyphosate alone.
“We’re going to have to go back to using residual herbicides,” Stephenson said. Residual herbicides should also be used for burndown applications, and farmers would be prudent to consider returning to tillage along with more frequent crop rotations.
Tall waterhemp in some areas of Louisiana is suspected of being herbicide-resistant, he said.
University of Arkansas weed scientist Ken Smith said herbicide-resistant pigweed is a major problem for commercial agricultural production. “It is much worse than I ever anticipated.”
He said one pigweed plant can produce 1.8 million seeds.
More than three dozen farmers gave presentations on their operations and the various conservation practices they use. Herbicide- resistant weeds often were included in their discussions.
Steve Stevens from southeast Arkansas said he uses Liberty Link cotton as an alternative to Roundup Ready crops. He said a yield drag was noticeable in the first few years, but it has become less of a problem. He said Ignite herbicide seems to be weaker on some grasses, and it is less effective during a drought, even more so than Roundup.
LSU AgCenter soybean specialist Ron Levy said Liberty Link soybeans are a good option for farmers facing herbicide resistance. “Ignite herbicide controls a broad spectrum of weeds including most glyphosate resistant weeds,” he said. “The rate for Ignite is 36 ounces for a single application or two 22-ounce applications.”
(This article was published in the winter 2011 issue of Louisiana Agriculture Magazine.)