Palmer amaranth

Palmer amaranth stems are smooth and hairless. This is in contrast to redroot pigweed and smooth pigweed, which have fuzzy hairs on the stems, especially the new stem growth. Photo: Annie Klodd, Penn State

Palmer amaranth stems are smooth and hairless. This is in contrast to redroot pigweed and smooth pigweed, which have fuzzy hairs on the stems, especially the new stem growth. Photo: Annie Klodd, Penn State

Palmer whisker zoomed

Often, but not always, Palmer amaranth leaves have a small “whisker” or pointed hair on the tip of the leaf.

 Herbicide resistant populations:

  • Group 2 + 9
  • Group 2
  • Group 3
  • Group 5
  • Group 9
  • Group 14
  • Group 27
  • Group 9 + Group 14
  • Group 5 + Group 27
  • Group 5 + Group 9

Locations of resistant populations:

Alabama, Arizona, Arkansas, California, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, New Mexico, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, Wisconsin, Virginia

Resources:

VIDEO: Palmer Amaranth and Waterhemp Identification РFrom Pigweed Management Video Series РPenn State

8 Key Points to Palmer Amaranth and Waterhemp Identification

The Grim reality of ‘Pigweed Patrol’ – Farm Journal

Video – Palmer amaranth ID and management – Penn State

Palmer amaranth Management in Illinois – University of Illinois

Palmer Amaranth Identification, Biology, and Management – Purdue University

Palmer Amaranth Control – Kansas State University

Palmer amaranth could affect Illinois soybean yield

Up-to-date info from U of Minnesota on the management and spread of Palmer Amaranth in the state

Pictorial Guide for Aid in Identifying Palmer Amaranth and Waterhemp – University of Minnesota

Palmer Amaranth and Waterhemp – New Threats to Pennsylvania Agriculture – Penn State

Detailed Palmer amaranth information – ID and management – Penn State