Determining the incidence of herbicide resistance in Australian grain cropping

Herbicides are the dominant weed management tactic in grain cropping systems. However, the effectiveness of this as a tactic can be variable due to the ability of susceptible weeds to develop resistance to these herbicides. There are currently 47 weed species which have confirmed herbicide resistance status in Australia. These are resistant to 10 different Modes of Action. Thirty of these species are known to be grain cropping weeds. It has been estimated that Australian grain growers spend an extra $8.24/ha to control herbicide resistant weeds, over$187M per annum.

Understanding the incidence and extent of herbicide resistant weeds can have multiple benefits. It identifies where investment is required to develop strategies to manage and prevent resistance. In addition, if communicated effectively, increases industry awareness leading to increased resistance testing by advisers and growers through commercial services. This allows optimal weed management decisions to be made.

Random surveying at a national scale is best to achieve this overall picture. Whilst advances have been made in achieving a national survey, there are still legacies of individual approaches. A clear opportunity exists to standardise survey and screening methodology leading to clear translatable messages. Another opportunity is to collate the historical testing data into a central repository.

The strategic communication of results can raise awareness of herbicide resistance and promote grower resistance testing.

Outcome

By 2023, 5% of growers have reduced the additional cost of managing herbicide resistant weeds by 10% through increased knowledge of the herbicide resistance status of key weeds of grain cropping systems in Australia.

Output 1

By December 2021, provide to GRDC a consolidated Australian grain herbicide resistance data set.

Details:

• Data to include historic herbicide testing results from previous random surveys.
• The metadata associated with the dataset will follow a recognised metadata schema that characterises the data to the extent that the means of its acquisition be repeatable and that the data it references is apt for comparison with other herbicide resistance data nationally and internationally.
• Licences for sharing and access of the data set will be established following an ‘open by default’ approach, within commercial and legal constraints

Output 2

By July 2023, Deliver to GRDC the resistance status of major winter and summer grain cropping weeds to key herbicides across the Australian grain growing regions.

Details:

• The Australian grain growing region to be surveyed once during the period of the investment.
• It is envisaged that the total number of target weeds would not exceed seven per seasonal rainfall region. However, the target weed species and herbicides should be based on clear rationale, display a value proposition and determined in final consultation with GRDC. Weed species may be regionally specific.
• Standard methodology for the survey and the resistance testing to be applied nationally.

Output 3

By July 2023, development and delivery of a communications package nationally to inform industry of the herbicide resistance status of key cropping weeds and the benefits of grower herbicide resistance.

Details:

• Package to include current and historic testing results.