Glyphosate resistant annual ryegrass, NSW.
Photo: Andrew Storrie, NSW DPI

Tip the scales in your favour to minimise the risk of glyphosate resistance in annual ryegrass

Risk increasing factors
• Continuous reliance on glyphosate pre-seeding
• Lack of tillage
• Lack of effective in-crop weed control
• Frequent glyphosate-based chemical fallow
• Inter-row glyphosate use (unregistered)
• Frequent croptopping with glyphosate
• High weed numbers

Risk decreasing factors
• The double knock technique*
• Strategic use of alternative knockdown groups
• Full-cut cultivation at sowing
• Effective in-crop weed control
• Use alternative herbicide groups or tillage for inter-row and fallow weed control
• Non-herbicide practices for weed seed kill
• Croptopping with alternative herbicide groups
• Farm hygiene to prevent resistant seed movement

*The double knock technique is defined as using a full cut cultivation OR the full label rate of a paraquat-based product (Herbicide Group L) following the glyphosate (Herbicide Group M) knockdown application.

What you do if you suspect glyphosate resistance

All Group M herbicides are glyphosate herbicides.

This guide is based on original concept for minimising glyphosate resistance in annual ryegrass in southern Australian grain growing by Paul Neve, WAHRI, University of WA. Optimal management techniques for other weed species may differ.

This guide has been produced by the Australian Glyphosate Sustainability Working Group, a collaborative initiative aimed at promoting the sustainable use of glyphosate in Australian agriculture.

The AGSWG gratefully acknowledges the financial support of the  GRDC.