Ontario Weed Committee

Ontario Weed Committee

Table of Contents


The Ontario Weed Committee strives to provide a venue for people with an interest in weed management to interact, share ideas and work towards improving the management of detrimental weedy plants in Ontario.

Objectives of the Ontario Weed Committee:

  1. To identify issues related to weed management and deficiencies in the management of weedy plants that negatively affect Ontarians; to compile and publish this list annually (Summer meeting – 2nd Wednesday of July).
  2. To compile and publish confirmed populations of herbicide resistant weeds in Ontario; to nudge Ontario agriculture towards adoption of integrated management practices that reduce the risk of selecting for herbicide resistant weeds (Summer meeting – 2nd Wednesday of July).
  3. To review the content and layout of the Ontario Crop Protection Hub. To provide constructive feedback and support that will improve the quality of this resource and ensure that it is available to Ontarians well in advance of the growing season (Fall meeting – 1st Wednesday of November).
  4. To showcase weed management research initiatives in Ontario (Summer and Fall meeting).


The Ontario Weed Committee is made up of individuals who are involved in weed management at some level, be it as a primary producer, researcher, agronomist, commodity organization or registrant. If you are interested in becoming a member, contact the Chair.

Meetings and Events:

Register: Ontario Weed Tour – Thursday July 13, 2023

Where: Elora Research Station https://goo.gl/maps/rEiCwsWurLpGjJxh9

Start time: 10:00 am

Certified Crop Advisor CEU’s: Available


Register: Fill out this form or call 1-877-424-1300

Two meetings will be held each calendar year:

The first will be held at one of the public research stations (Elora, Harrow, Huron Park, Ridgetown, Simcoe or Woodstock) during the 2nd thursday of July. The purpose of this meeting is to:

  1. View select research trials conducted on the host research station.
  2. To identify gaps in management solutions for weedy plants that negatively affect Ontarians.
  3. To provide a progress update on key initiatives being taken on by the committee.
  4. To prompt registrants to identify any new additions or revisions to the Crop Protection Hub (so that the process of updating the guide can begin).

The second meeting (aka: fall meeting) will be held the first Wednesday of November, which should be the day after the Ontario Pest Management Conference. The purpose of this meeting is to:

  1. Review revisions and information being added to the Crop Protection Hub
  2. Provide an annual summary of OWC activities and deliverables
  3. State goals for the upcoming field season

Elected Positions:

Leanne Freitag – CHAIR

Marijke Vanderlaan – VICE CHAIR

Mike Cowbrough (OMAFRA) – SECRETARY

Kristen Obeid (OMAFRA) – TREASURER

Weeds of concern for agricultural production in Ontario:

  1. lamb’s-quarters
  2. Canada fleabane
  3. common ragweed
  4. giant ragweed
  5. foxtail species
  6. pigweed (redroot and green)
  7. waterhemp
  8. wild carrot
  9. perennial sow-thistle
  10. bluegrass species
  11. fall panicum
  12. wild oats
  13. vetch
  14. velvetleaf

Terms of Reference

Crop Protection Hub – Submission process

Contact the following editors regarding submission timelines and process.

Mike Cowbrough (OMAFRA) – (FIELD CROPS)