A single Palmer amaranth plant, if allowed to grow to maturity, can produce as many as 1 million seeds. / Photo provided by Purdue University
At a glance
Growers who identify what they believe to be Palmer amaranth are encouraged to report it to Bill Johnson, Purdue professor of weed science, at 765-494-4656 (wgj@purdue.edu) or Travis Legleiter, Purdue weed science specialist, at 765-496-2121 (tlegleit@purdue.edu)
Their recommendations:
• In general, the best method of control is a multistage approach that includes crop rotation, thorough tillage, full rates of pre-emergence residual and postemergence herbicides, hand weeding, monitoring ditches and field borders, and cleaning equipment before moving from infested to non-infested fields.
• Growing corn for a few years consecutively might be the best option for growers who don’t want to invest in expensive soybean herbicide programs.
• Herbicides are available for treating the plant in ditches and fencerows.
See Johnson and Legleiter’s publication, Palmer Amaranth Biology, Identification, and Management, available for free download from Purdue Extension’s The Education Store at http://www.the-education-store.com. Search for WS-51.
Where it is:
Here is the list of counties near Tippecanoe where Palmer amaranth has been confirmed as of July 10: Benton, Cass, Jasper, Newton, Pulaski and White. Here are 12 other counties where it has been found: Adams, Clay, Henry, Huntington, Kosciusko, LaPorte, Noble, Porter, Posey, St. Joseph and Vanderburgh.
A fast-spreading, herbicide-resistant weed with a villainous-sounding name is spreading noxious roots in 17 Indiana counties and may have a toehold in Tippecanoe, a Purdue University weed scientist says.
Palmer amaranth has been confirmed in 17 Indiana counties — up from seven last fall — and is no longer confined to the northwestern part of the state, says Bill Johnson, Purdue professor of weed science. It’s been spotted in several counties next to or near Tippecanoe County.
Palmer amaranth is no ordinary weed. It packs a trio of characteristics that pose potentially costly challenges to producers, particularly soybean farmers, wherever it is found.
“One or two plants in an 80-acre cornfield can cause a train wreck the following year,” Johnson said.
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