Before Palmer amaranth became resistant to glyphosate, farmers were spending about $23 per acre, he said. The extra costs for glyphosate-resistant Palmer amaranth management are proving to be detrimental to cotton farmers. This is what drives researchers like Culpepper to find a better solution.

“Folks like myself, that’s really our overall objective — figuring out how to implement new programs that are effective but more economically sustainable,” Culpepper said. “Palmer amaranth has changed the world of agriculture like no other weed.”


Want the latest in ag news delivered daily to your inbox? Subscribe to Southeast Farm Press Daily.


The crop-altering weed makes picking cotton almost impossible due to its enormous growth potential. According to Culpepper, when conditions are favorable, Palmer amaranth can grow an inch and a half or two inches per day. It can reach a height of 7 to 10 feet tall. The overwhelming size of the plant can also adversely affect cotton equipment moving through a field.

Palmer amaranth can also rob cotton plants of much-needed resources. It competes for moisture and steals nutrients cotton. The result is reduced cotton yields.

Reproduction factors in Palmer amaranth’s role as a dominant pest, too. A female plant can produce approximately 400,000 seed in dry land production. In irrigated fields, seed production can reach 750,000 per female plant.

Despite the damage inflicted by Palmer amaranth, Culpepper believes progress has been made in the fight to manage it.

 “We are making progress, but that’s only for growers that are aggressive and staying the course every year. You can’t miss one year. If you miss one year, because so many seed are produced, you’re back to ground zero,” Culpepper said.

For more information about Palmer amaranth and UGA’s programs to control it in cotton, visit


          More from Southeast Farm Press

Deadline is June 10 for Southeast grain scholarships

Thrips making run at North Carolina cotton

Native warm-season grasses weather drought, provide many other benefits

Applicants sought for ASA/DuPont Young Leader program

Hog profits return, but delayed crop planting keeps producers wary