Screening false cleavers from the Prairie Herbicide Resistance Surveys for quinclorac and glyphosate resistance

Key Result

This project will provide an indication of how quickly these quinclorac and glyphosate resistance in cleavers may be increasing or spreading on the Prairies. This will thereby contribute directly to the development of technologies, strategies and recommendations which help growers mitigate or reduce selection pressure for weed resistance.

Project Summary

Overview

Quinclorac resistance has previously been documented in Alberta, and cleavers have been identified as a high risk species for glyphosate resistance in the Prairies. However, there is no proactive screening ongoing for these herbicide resistant biotypes. There are samples available for screening from the Prairie Herbicide Resistance survey, but that project does not have the capacity to add screening to these additional herbicides.

This project will screen false cleavers (hereafter cleavers) samples from the Prairie Herbicide Resistance surveys from 2014-2017 and 2019-2023 for resistance to quinclorac and glyphosate resistance.

Purpose

Building on the ability of the Prairie Herbicide Resistance Survey to screen and identify HR weeds in the Prairies, this project uses samples from the resistance surveys and screens for presence and frequency of quinclorac and glyphosate resistance in cleavers on the Prairies. This is particularly important with the increased use of quinclorac for cleavers management since approvals of the MRLs in recent years.

This project will produce maps showing the frequency and distribution of these herbicide resistant biotypes in two time frames, to give us an indication of how quickly these biotypes may be increasing or spreading. The knowledge generated from this will contribute directly to the development of technologies, strategies and recommendations which help growers mitigate or reduce selection pressure for weed resistance.

Objectives

Specific project objectives includes:

  • Screening false cleavers samples collected in the 2014-2017 Prairie Herbicide Resistance Survey for quinclorac resistance.
  • Screening false cleavers samples collected in the 2019-2023 Prairie Herbicide Resistance Survey for quinclorac resistance.
  • Screening false cleavers samples with remaining seed from the 2014-2017 and 2019-2023 Resistance Surveys for resistance to glyphosate.
  • Creating maps of presence/frequency of quinclorac and glyphosate resistance on the Prairies from recent surveys, document changes in frequency over that time frame, and conduct technology transfer activities to let producers know the status of quinclorac and glyphosate resistance on the Prairies.
  • Publishing a scientific manuscript based on this resistance testing.