The first barley 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 barley grass for the herbicides listed. For detailed survey information on individual cropping zones, please click here.
2010
The first survey to assess the frequency of herbicide resistance in barley grass in grain producing areas of WA was conducted in 2010, with samples screened during 2012.
Analysis of 47 barley grass samples collected randomly from 466 paddocks across the State during this survey confirmed a small percentage of populations showing resistance to Group B herbicides, including both SUs and IMIs.
Major findings included:
- 6% of the populations sampled had resistance to SU herbicides
- 4% of these resistant populations also had cross resistance to the IMI herbicides
- 100% of populations were susceptible to both FOPs and DIMs, paraquat and glyphosate
- Group B resistance in barley grass appears to be more prevalent in central and southern areas of the WA wheatbelt
2015
A total of 42 barley grass samples were collected randomly from 509 paddocks across the State. These populations were screened with fluazifop, clethodim, sulfosulfuron, intervix®, paraquat and glyphosate. A small percentage of populations with resistance to Group B herbicides, including both SUs and IMIs was found
Major findings included:
- 5% of the populations sampled had resistance to SU herbicides
- 2% of these resistant populations also had cross resistance to the IMI herbicides
- 5% of populations had plants with resistance to fluazifop
- 100% of populations were susceptible to DIMs, paraquat and glyphosate
- Resistance levels are similar to the 2010 survey.
Herbicide rates
Herbicide rates used during resistance testing for samples collected during the 2010 survey.
| Barley 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 |
| 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
