Minnesota: Palmer Pigweed Still Spreading – What You Should Know

Palmer amaranth in southern Illinois. Photo: Robert Bellm, University of Illinois

Palmer amaranth in southern Illinois. Photo: Robert Bellm, University of Illinois

Tracking Palmer amaranth in Minnesota

Palmer amaranth in Minnesota started with just one pathway of spread – a single company selling contaminated native seed mix for conservation plantings. Nearly two years later, Palmer continues to spread by other means, including via humans, equipment, livestock, hay, forage and feed.



In 2018, Palmer was reported at 44 sites across 6 counties. This includes the first sightings of Palmer in soybean fields. MDA’s Noxious Weed and Hemp Unit Supervisor Tony Cortilet discusses Minnesota’s response to date.

How can you help slow the spread?

>>Watch Tony’s presentation on YouTube (18 min)

Fostering strong communication ties for better management



Palmer amaranth is one of the most difficult weeds to manage in the field. It has already shown resistance to five major classes of herbicides across the U.S.. Combine the challenge of resistance with an aggressive growth rate, prolific seed production, prolonged emergence and peak heights of 6-8 feet, and yield losses can reach 80-90 percent for corn and soy growers.

UMN Weed Science Extension specialist Jeff Gunsolus believes the key to stopping an invader as aggressive as Palmer lies in community cooperation, coordination and communication.

How can you work within your community to manage Palmer amaranth?

  • Report sightings as soon as they happen to prevent spread.
  • Adopt a zero tolerance policy for Palmer.
  • Talk to your neighbor about Palmer amaranth and your plan for management.
  • Develop a “triangle of trust” between consultants and farmers, MDA and UMN Extension.

>>Watch Jeff’s presentation on YouTube (16 min)

Screening native mixes for noxious weeds



Each year, the Minnesota Seed Regulatory Program inspects 1600-2000 samples to ensure compliance with state seed law. MITPPC-funded researchers are currently developing new genetic markers to better identify Palmer amaranth in seed mixtures. Their work will dramatically increase the sample volume seed analysts can test, improving accuracy while lowering overall cost.

MDA Seed, Weed, Hemp & Biotechnology Program Supervisor Denise Thiede discusses Minnesota seed labeling guidelines at the video link. Or try your hand at visually identifying amaranth seed species below (no cheating!)

>>Watch Denise’s presentation on YouTube (18 min).

Watch the #PalmerSummit at home

You can catch the entire presentation lineup at home via our YouTube channel. Check out the full playlist here, including presentations not covered in this post, and keep sharing your thoughts on Twitter using the hashtag #PalmerSummit.

Questions or comments on any of these issues? Please contact us at the Minnesota Invasive Terrestial Plants and Pests Center.

Source URL: https://blog-crop-news.extension.umn.edu/2019/04/waiting-for-spring-there-is-plenty-of.html