A new Herbicide Resistance Management Strategy (HRMS) for Australian cotton

Abstract

Australian cotton's Herbicide Resistance Management Strategy (HRMS) was implemented in 2013 as a voluntary mechanism for slowing down and managing the then rapidly-worsening issue of glyphosate resistance in common weed populations. The HRMS, with its simple '2+2' approach, was widely adopted, and weed control diversity in Australian cotton has increased substantially since its introduction. However, recent developments in both over-the-top herbicide capabilities in new varieties, and the emergence of resistance in herbicides other than glyphosate, necessitate the evolution of the HRMS to cover more than just glyphosate. We redeveloped the HRMS using a similar approach to the 2013 version, using hundreds of simulations of multi-herbicide strategies in mixed weed populations, using the Diversity model. We present the new HRMS for 2025, and discuss the emerging state of industry regulation for herbicide tolerance traits and weed control.