Grains Research and Development

Annual ryegrass

Annual ryegrass  (Lolium rigidum)

Glyphosate Resistant Annual Ryegrass in wheat 
(Photo A. Storrie)

Annual ryegrass is one of the most serious and costly weeds of cropping systems in southern Australia.

Annual ryegrass is a problem for a number of reasons:

  • It produces an extremely high number of seeds per plant
  • It is highly competitive
  • Is a host for the bacteria Clavibacter spp. that cause annual ryegrass toxicity (ARGT)
  • It can be infected by ergot fungus
  • Many populations have developed resistance to both selective and non-selective herbicides

Further detail about this weed including integrated weed management tactics that could be considered when developing a management plan can be found in the section on problem weeds in the Integrated Weed Management Manual.

Further information

Ecology and biology of common weeds are outlined in section 6 of the Integrated Weed Management Manual

Update papers

Managing Clethodim resistant ryegrass (2016)

Why the obsession with the ryegrass seed bank? (2015)

Herbicides for control of clethodin-resistant annual ryegrass (2015)

Impact of crop rotations on profit, ryegrass seed bank, ryegrass dynamics and nitrogen in crop sequences in southern NSW where herbicide resistant annual ryegrass is a problem (2015)

Managing annual ryegrass in cropping systems - pre and post emergent herbicide trial, Barellan 2013  (2014)

New pre emergent herbicides for resistant ryegrass and brome grass (2010)

Proven enhancements in the knockdown control of seedling Annual ryegrass when using non-selective herbicides in tank mixtures with Boxer Gold (2009)

Other information


RIM (Ryegrass Integrated Management), provides insights into the long-term management of annual ryegrass in dryland broadacre crops facing development of herbicide resistance. RIM enables alternative strategies and tactics for ryegrass management  to be compared for profit over time and impact on weed numbers. The software’s underlying model integrates biological, agronomic and economic considerations in a dynamic and user-friendly framework, at paddock scale and over the short and long-term.

The tool tracks the changes through time on a 10 year crop cycle for ryegrass seed germination, seed production and competition with the crop. Financial returns are also estimated annually and as a 10 year average return.

A free download is available from:

New mode of action herbicides to combat herbicide resistant annual ryegrass (Lolium rigidum) in Australian cereal production
Peter Boutsalis, Gurjeet Gill and Christopher Preston pp. 278-280, 17th Australasian Weeds Conference (2010)

Spread of herbicide resistance alleles in Lolium rigidum Gaud. (annual ryegrass)
Jenna Malone, Peter Boutsalis and Christopher Preston pp. 258-261, 17th Australasian Weeds Conference (2010)

Impact of management on glyphosate-resistant Lolium rigidum populations on farm
Angela M. Wakelin and Christopher Preston pp. 80-82, 16th Australasian Weeds Conference (2008)

Annual ryegrass (Lolium rigidum gaudin) resistance to glyphosate and other herbicides in crops and pasture seed in northern New South Wales
SandeepNarwal, Brian M. Sindel and Robin S. Jessop p. 97, 16th Australasian Weeds Conference (2008)

Annual ryegrass control affected by choice of management system
Rex Stanton, James Pratley and David Hudson pp. 306-308, 16th Australasian Weeds Conference (2008)

BOXER® GOLD, a flexible new pre-emergent herbicide alternative for the control of annual ryegrass (Lolium rigidum Gaudin) and toad rush (Juncus bufonius L.) in wheat and barley
Craig A. Ruchs pp. 291-293, 16th Australasian Weeds Conference (2008)

The efficacy of Spray Seed® and Axial® herbicides on the narrow-leaved targets annual ryegrass (Lolium rigidum Gaudin) and oats (Avena spp.) when applied with a range of nozzle types and water volumes
Jason W.G. Sabeeney and Garth R. Wickson pp. 294-296, 16th Australasian Weeds Conference (2008)

Video Peter Newman on succesful control of multiple herbicide resistant lolium ryegrass with integrated strategies in WA