What is in this article?:
- Kentucky researchers tackle herbicide resistant weeds
- Fulton County problems
- Union County trials
Palmer amaranth and waterhemp share many similarities. They are in the pigweed family, are similar in appearance, produce male and female plants that must cross to reproduce and are problems in soybeans. Although both species have been in Kentucky for more than 10 years, problems controlling them with glyphosate did not appear until the past few years.
Union County trials
Witt and graduate student, Blake Patton, have confirmed the weed is glyphosate resistant in several counties and are working to determine if it is resistant to any other herbicides at a trial in Union County.
"Most of the worst cases of glyphosate resistance are in fields along the Ohio River, but glyphosate-resistant weeds are also found farther back from the river," said Rankin Powell, Union County Extension agent for agriculture and natural resources.
Witt believes growers will be able to control both Palmer amaranth and waterhemp, but it will require a different weed-management plan.
"We controlled weeds before we had products containing glyphosate, and we will control them again," he said.
While control trials for this weed are just beginning, growers can do a couple of things to minimize the spread of glyphosate-resistant waterhemp including removing the weeds while small to prevent seed production and rotate the field with corn. There is an effective herbicide against glyphosate-resistant waterhemp, but it's only available for use in corn.
Producers, who believe they have either weed on their property, should contact their county agriculture and natural resources Extension agent, so the weed can be identified.