By Scout Nelson
As harvest approaches, researchers at the University of Nebraska-Lincoln (UNL) are asking growers to help monitor herbicide-resistant weeds by submitting seed samples from suspected resistant populations. The effort aims to improve understanding of herbicide resistance across Nebraska and identify emerging resistance issues before they become widespread.
The project focuses on waterhemp and Palmer amaranth plants that survived herbicide applications during the 2026 growing season. By analyzing seed samples from these weed escapes, researchers can determine whether resistance or reduced herbicide sensitivity is present.
Resistance screening provides valuable information for both farmers and researchers. The results help guide future weed management decisions while supporting statewide monitoring efforts.
Waterhemp is more common in eastern Nebraska, while Palmer amaranth is typically found in western parts of the state. Both species can produce large numbers of seeds, allowing resistant populations to spread quickly if not properly managed.
Researchers are especially interested in weeds that survived applications of 2,4-D, dicamba, or glufosinate products. While resistance to glyphosate and ALS-inhibiting herbicides is already widespread, scientists are investigating whether resistance to additional herbicide groups is developing.
Growers can participate by collecting mature seed heads from at least five female plants that survived herbicide treatments. Samples should be placed in paper bags and submitted with a completed resistance screening form.
Seed samples can be delivered to local Nebraska Extension offices or mailed to designated UNL laboratories in Lincoln or North Platte. Researchers will then conduct greenhouse screening and additional testing to determine the level of herbicide resistance present.
Scientists note that weed escapes do not always indicate herbicide resistance. Factors such as weather conditions, application timing, spray coverage, and late weed emergence can also affect herbicide performance.
To help slow resistance development, UNL specialists encourage growers to rotate herbicide modes of action and incorporate integrated weed management practices such as cover crops and narrower row spacing. These strategies can help preserve effective weed control options for the future.
Photo Credit: gettyimages-zoomtravels
Categories: Nebraska, Crops