Many producers have a poor understanding of how and why herbicide resistance develops and are yet to adopt integrated weed management strategies that effectively manage it.

This is the feedback from consultants and agronomists in a recent survey by the EH Graham Centre for Agricultural Innovation, 20 years after herbicide resistance was raised as one of the major management challenges facing future farming systems.

This is a timely wake-up call as we enter an era of GM herbicide-tolerant crops, says Helen Burns, research liaison officer for the Graham Centre.

Last year Ms Burns conducted a preliminary survey of public and private NSW consultants and agronomists to gauge the level of adoption of integrated weed management (IWM) strategies by grain producers in the southern NSW cropping zone.

The survey was part of the Graham Centre’s GRDC funded Integrated Weed Management project.

Advisors were asked to comment on their clients’ understanding and management of herbicide resistance.

"Responses indicated that although awareness of herbicide resistance is generally good and a proportion of producers manage it effectively and have a sound understanding of IWM, many producers do not," Ms Burns said.

"Advisors suggested that producers only accept herbicide resistance as a significant issue when they are hit with a resistance "blow out" that clearly impacts on their business.

"Impact on profit is the motivation producers need to adopt IWM strategies.

According to Ms Burns, it is concerning that advisors consider there is "a lot of misunderstanding", that Hoegrass is still being used because it is a cheap option, and poor weed control is often incorrectly blamed on poor application technique and/or moisture stress.

Ms Burns suggests that there are a number of issues that have left the herbicide resistance message more clouded for southern NSW grain producers:

Weed management strategies have traditionally focused on chemical solutions and there is limited information on the cost/benefit of non-chemical strategies and the financial penalties of inaction on herbicide resistance.

Producers are continually looking for a silver bullet, fuelled by the regular release of new formulations of old chemical groups with new names and associated advertising claiming improved levels of control.

In recent seasons many grain producers have had more than enough to worry about without facing complexities associated with managing herbicide resistance.

Changes in emphasis of southern NSW extension programs from specific herbicide resistance programs to more general agronomy and weed management may have implied that herbicide resistance was no longer an issue in the region.

The message needs revitalising - it is 20 years old and is often preached by out-of-State experts relaying experiences from farming systems considered irrelevant by local producers.

Advisors suggest that the IWM message needs to include up to date local data, delivered by experts working in local farming systems.

Insidious, chronic problems that evolve over time, such as herbicide resistance, which need on-going vigilance and elevated management skills, require different education and extension strategies to those that promote simple solutions with immediate, easily measured benefit.

Contact Helen Burns (02) 6938 1947, helen.burns@dpi.nsw.gov.au or Hanwen Wu (02) 6938 1602, hanwen.wu@dpi.nsw.gov.au or Eric Koetz (02) 6938 1954, eric.koetz@dpi.nsw.gov.au

Further reading

NSW DPI weeds research