David Brunton

David Brunton

Higher Degree by Research Candidate

School of Agriculture, Food and Wine

Faculty of Sciences


Annual ryegrass (Lolium rigidum) is a major, out-crossing annual grass species that has evolved resistance to many common herbicides used in broad acre cropping systems across southern Australia. Repeat selection with herbicides has resulted in widespread resistance to many commonly used pre- and post-emergent herbicide sites of action, including Groups A, B, D, M and L. Resistance evolution to selective post-emergent herbicides has resulted in increased reliance on pre-emergent herbicides to manage L. rigidum. The most widely used herbicides in cereals for the control of L. rigidum are Groups J and K. More recently resistance was detected to the Group J herbicides triallate (Avadex Xtra®) and prosulfocarb (Arcade and Boxer Gold®) has occurred. Resistance evolution to Group K herbicide Sakura® (pyroxasulfone) is of greatest concern as this remains the last herbicide available for control of L. rigidum in wheat. Investigating Group J and K herbicide resistance will provide valuable information to the agricultural community and allow advisers and growers to manage these herbicides going forward.


Topic: Investigating the evolution and management of Group J and K resistance in annual ryegrass (Lolium rigidum). 

The study objectives are to:

• Undertake a series of dose-response experiments using multiple group J and K herbicides, to quantify
and characterise (including LD50 values) resistant annual ryegrass populations;
• Determine the level of cross-resistance to group J and K herbicides;
• Identify the mechanism(s) that confer resistance to Group J herbicides;
• Determine the mode of inheritance in ryegrass populations resistant to group J and K herbicides;
• Develop alternative herbicide strategies in cereal rotations to effectively manage group J and K resistant ryegrass.

Farmer focus group

Grower update at Paskeville field trial site, Yorke Peninsula 2018.

Ryegrass biotype treated with pre-emergent herbicides.  Left to right: Untreated, TriflurX®, Avadex Xtra®, Arcade® and Sakura®.

L. rigidum biotype treated with pre-emergent herbicides. Left to right: Untreated, TriflurX®, Avadex Xtra®, Arcade® and Sakura®. 

Group J herbicide dose-responses

Group J herbicide dose-responses: Resistant L. rigidum biotype (far back) vs two susceptible biotypes (front 2 rows). L. rigidum plants were sprayed with increasing amounts (L-->R) of triallate (top photo) or prosulfocarb (bottom photo).

Inhibitor experiments determining potential resistance mechanisms in Group J resistant L. rigidum

Investigating Group J herbicide resistance mechanisms in L. rigidum. Front row: susceptible L. rigidum treated with prosulfocarb (Arcade®) only. Back row: Susceptible L. rigidum treated with inhibitor + prosulfocarb.

  • Journals

    Year Citation
    2019 Brunton, D. J., Boutsalis, P., Gill, G., & Preston, C. (2019). Resistance to very-long-chain fatty-acid (VLCFA)-inhibiting herbicides in multiple field-selected rigid ryegrass (Lolium rigidum) populations. Weed Science.
    2019 Brunton, D., Boutsalis, P., Gill, G., & Preston, C. (2019). Resistance to very long chain fatty acid (VLCFA)- inhibiting herbicides in multiple field selected rigid ryegrass( Lolium rigidum) populations. Weed Science, 67(3), 267-272.
    DOI WoS1
    2018 Brunton, D., Boutsalis, P., Gill, G., & Preston, C. (2018). Resistance to Multiple PRE Herbicides in a Field-evolved Rigid Ryegrass (Lolium rigidum) Population. Weed Science, 66(5), 581-585.
    DOI Scopus3 WoS4
  • Conference Papers

    Year Citation
    2018 Brunton, D., Boutsalis, P., Gill, G., & Preston, C. (2018). Control of thiocarbamate resistant annual ryegrass (Lolium rigidum) in lentils (Lens culinaris) in southern Australia. In 21st Australasian Weeds Conference Proceedings (pp. 12-15). Manly, Sydney.

This research is funded by a GRDC Research Scholarship and The University of Adelaide. 

Demonstration assistance in:

Agricultural Systems I (A and B)

Pasture and Crop Production II

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