Blog & News

Harmonized surveillance for monitoring invasive amaranth species in Canada

Published on Wednesday January 24, 2024
Authored by PEIISC

This week’s council member post is from Andrew McKenzie-Gopsill, PhD, Research Scientist – Weed Science with Agriculture and Agri-Food Canada, Charlottetown Research and Development Centre and co-chair of the PEI Invasive Species Council.

Early detection of invasive species is critical for successful management. While often invasive species management is focused on natural areas, many of the most troublesome agricultural weeds are also non-native. Redroot pigweed (Amaranthus retroflexus) and green pigweed (Amaranthus powellii) are common aggressive agricultural weeds across PEI. Several other species within the Amaranthus genus including Palmer amaranth (Amaranthus palmeri) and common waterhemp (Amaranthus tuberculatus) are similarly competitive weeds that in a worst case scenario can lead to complete crop failure. Also, several biotypes of these species are resistant to upwards of eight different herbicides, reducing the tools available to farmers for their management and requiring increasingly complex weed management programs. Currently, common waterhemp is limited to agricultural fields in Ontario, Quebec, and Manitoba, whereas Palmer amaranth has yet to be detected in Canada. To facilitate early detection and rapid response, the Weeds Surveillance Community of Practice, a sub-committee of the Canadian Plant Health Council, developed a harmonized surveillance protocol that has been rolled out across the country. This protocol includes:

  1. Biosecurity protocol to prevent spread of amaranth species during site visits including site entry and exit procedures.
  2. A visual key for identification of common amaranth species
  3. List of data to collect about the field location, crop history, and management
  4. Estimation of amaranth species phenology and field distribution
  5. Methods for scouting amaranth species throughout the season
  6. List of available labs for molecular species identification and herbicide resistance testing
  7. Sampling procedure for molecular testing
  8. List of regional contacts for more information and to report a sighting

Help prevent the introduction and spread of invasive amaranth species. Learn how to identify and differentiate Palmer amaranth and common waterhemp from other pigweed species and get in touch with the PEIISC or anyone with the Weeds Surveillance Community of Practice.

Expanded surveillance and monitoring information can be found in the CFIA’s survey protocol document. View or download a PDF copy below:

For more information on the Canadian Plant Health Council, check out the link below:

Above: A field of corn infested with herbicide-resistant redroot pigweed.
Photo by Andrew McKenzie-Gopsill

Above: Identification key for common amaranth species in Canada and the United States