Game changer: Palmer amaranth vs. Cornbelt farmers
What do these have in common: a grand slam home run, a hole-in-one, a pick six, Palmer amaranth? The answer is that they are all game changers. As many Cornbelt farmers harvested their crops this fall and found the tall spindly seed heads of Palmer amaranth, they realized it was too late in 2013 to do anything about it. After all, weed specialists had been urging farmers to carefully cut the weeds, remove them from fields in plastic bags, and burn them. If that did not get accomplished in 2013, what can be done in 2014 to plan for hundreds of thousands more Palmer amaranth in that field which normal weed control may not touch?
“Among the weedy species of Amaranthus, Palmer amaranth has the fastest growth rate and is the most competitive with the crops common to Midwest agronomic cropping systems.” That is the assessment of Aaron Hager, University of Illinois Extension weed specialist, who says confirmed reports indicate it will cut soybean yields by nearly 80% and corn yields by over 90%. The weed is originally from the southwestern U.S., but in 1957 weed specialists said he was on a northeastward movement. While it may not be in every county, USDA plant ecologist Adam Davis says, “There are few landscape-level barriers to the establishment of Palmer amaranth populations in Illinois, and that these populations, once established, are competitive with crop species. In other words, these results indicate that it’s not a question of if Palmer amaranth will become established in Illinois, but rather when and where it will become established.” While his observation follows research in Illinois, the conclusion could be applied to nearly every state.
"So just spray a little glyphosate on it." While that may control some of the plants the first year, it may have little impact the second year, says Hager, “Palmer amaranth can be effectively managed in Illinois agronomic crops, but the greatest likelihood for successful management is with systems that employ multiple effective management tactics. Palmer amaranth is perhaps the personification of a weed species that requires an integrated management approach.”
The female plants produce an abundance of seeds, which are spread by birds, furry-footed wild animals, dirt clods on tillage equipment, and particularly by combines. And farmers who operate across wide expansive areas are more likely to quickly spread the seed than those who remain close to home.
So how do you control Palmer amaranth? Hager and other weed specialists recommend some specific precautions where the plants exist: