Australian Herbicide Resistance Initiative (AHRI)

Brome grass

Brome grass

The first brome grass survey was conducted in 2010 to determine the frequency and extent of herbicide resistance in the WA grain belt.

The graph below provides a summary of the herbicide resistance status of brome grass for the herbicides listed. For detailed survey information on individual cropping zones, please click here.


Bar chart


The first survey to assess the frequency of herbicide resistance in brome grass was conducted in 2010, with samples screened during 2012.

Analysis of 91 brome grass samples collected randomly from 466 paddocks across the State during this survey has confirmed a small percentage of populations showing resistance to Group B sulfonylurea (SU) herbicides,

Major findings included:

  • Around 13% of  populations showed resistance to SU herbicides
  • Only one population of brome grass showed resistance to the Group A herbicides including both FOPs and DIMs
  • Group B resistance in brome grass appears to be more prevalent in northern areas of the WA wheatbelt


A total of 97 brome grass samples were collected randomly from 509 paddocks across the State. These populations were screened with fluazifop, clethodim, sulfosulfuron, intervix ®, metribuzin, paraquat and glyphosate.

Major findings included:

  • 24% of populations showed resistance to SU herbicide sulfosulfuron
  • One population of brome grass had resistance to the Group c herbicide metribuzin
  • All populations were susceptible to fluazifop, clethodim, glyphosate and paraquat
  • Group B resistance in brome grass has increase by 9% since 2010 and has also become prevalent in southern areas of the WA wheatbelt

Herbicide rates

Herbicide rates used during resistance testing for samples collected during the 2010 survey.

Note that brome was tested with both Monza® (sulfosulfuron) and Oust® (sulfometuron). If brome was resistant to Oust®, it was also resistant to Monza®, however Oust® allowed for better discrimination between resistant and susceptible plants.

Brome grass
Product Label rate Active ingredient Active rate (gai/ha)
Fusilade® 610 mL/ha Fluazifop 78
Gramoxone® 1.2 L/ha Paraquat 300
Intervix® 700 mL/ha Imazamox + Imazapyr 23 + 10.5
Monza® 50 g/ha Sulfosulfuron 37.5
Oust® 40 g/ha Sulfometuron 30
Roundup® 1.5 L/ha Glyphosate 810
Select® 250 mL/ha Clethodim 60

Related publications

Owen, M.J., Martinez, N.J. and Powles, S.B. (2015) Herbicide resistance in Bromus and Hordeum spp. in the Western Australian grain belt. Crop and Pasture Science, 66, 466-473

Owen, M.J., Goggin, D.E. and Powles, S.B. (2012) Non-target-site-based resistance to ALS-inhibiting herbicides in six Bromus rigidus populations from Western Australian cropping fields.Pest Management Science, 68, 1077-1082.

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