How an Australian approach could beat blackgrass

A unique research and knowledge transfer initiative is helping Australian grain producers tackle their most damaging agronomic threat – herbicide-resistant weeds.

In the UK, each major agrochemical and distribution group has its own blackgrass trials site where cultural and chemical control methods are put to the test.

The information generated and passed on through open days and media outlets is undeniably valuable, but some can take a slightly different spin on how to best tackle the problem.

See also: How to prevent glyphosate resistance in blackgrass

In addition to commercial companies, AHDB Cereals & Oilseeds and independent research bodies such as Rothamsted and Niab Tag also publish a deep pool of information to draw from.

With such crowded information streams, it can be confusing for UK farmers. To avoid this, the Australian grains industry has taken a different approach and united to provide clear and consistent messaging on integrated weed control.

How bad is Australia’s herbicide-resistant weed problem?

An annual Australian Herbicide Resistance Initiative (AHRI) survey takes annual ryegrass weed seed samples from 500 randomly selected fields across Australia for sensitivity testing to commonly used herbicides.

The results for 2017 had just arrived as Farmers Weekly paid the AHRI a visit in Perth:

  • 99% resistant to ALS inhibitors (for example, sulfonylureas)
  • 96% resistant to ACCase inhibitors (fops, dims, dens)
  • 30% resistant to trifluralin
  • 7% resistant to glyphosate
  • 2% resistant to atrazine

Although there are differences between regions in Australia’s vast grain growing areas, a Grains Research and Development Corporation report outlines some of the key weed control challenges at a national level.

  • The overall cost of weeds to Australian grain producers is about $3.3bn (£1.9bn).
  • Weeds cost the average grower $146/ha (£83/ha) in costs and yield loss.
  • The average cost of weed control is about $113/ha (£65/ha).
  • The costliest weeds are ryegrass, wild radish and wild oats – all species with widespread resistance to several herbicide modes of action.
  • Herbicide-resistant brome is an up-and-coming weed.
  • Herbicide resistance costs the Australian grain industry about $187m (£107m) in additional herbicide application, on top of non-chemical integrated strategies.

Getting resistance message across

The Perth-based Australian Herbicide Resistance Initiative (AHRI) is a national research and communication team founded 20 years ago after the problem of herbicide resistance was recognised as a serious threat to the sustainability of Australia’s grains industry.

Funded by the Grains Research and Development Corporation (GRDC) levy board, it is allocated about $1m (£560,000) each year and a hefty 35% of its budget is spent on communications.

AHRI centre manager Lisa Mayer says changing farm practices and the overuse of herbicides has accelerated the risk of resistance – so delivering messages to help extend the life of herbicides is key to turning the tide.

To deliver these messages the AHRI team has taken full advantage of the internet and social media.

With the backing of multiple industry stakeholders – including major agrochemical manufacturers – the WeedSmart initiative evolved, supported by a further $100,000 annual funding from GRDC and $200,000 from industry.

Now five years old, it aims to build an online community through platforms such as Twitter and Facebook, where practical advice can be delivered direct to growers for implementation in the field.

“It is very difficult to get out and see farmers in Australia face to face, so we use digital and online media to close this gap,” Ms Mayer says.

Many have now adopted Twitter as their main form of communication to network with each other, tap into peer knowledge and receive messages from agriculture extension specialists.

“It is about delivering messages that people relate to and WeedSmart has now become an important source of information for farmers and agronomists across the country,” Ms Mayer says.

WeedSmart – tackling resistant weeds online

  • 45,000 website page views from 18,000 users during 2017
  • Users are predominantly Australian (80%), but also from the US (7%), Canada (3%) and several other countries from South America, Europe, Asia and New Zealand
  • Just under half of users find the WeedSmart website via social media platforms
  • @WeedSmartAU has more than 3,300 followers on Twitter and more than 2,000 likes on Facebook
  • More than 1,400 subscribers on the WeedSmart blog
  • 27 Podcasts with almost 6,200 plays

Note: Figures accurate December 2017

Multi-layered weed control

WeedSmart hammers home six vital integrated weed control practices and offers some extra snippets of advice covering areas such as spray application and herbicide resistance testing.

On its website, each of the “Big 6” is displayed and users can follow links through to more detailed information on each, including helpful videos and extra reading.

Supplementing this is an “ask the expert” forum – hosted by a different WeedSmart expert each month – plus farmer case studies, factsheets, webinars and podcasts.

You can even download a WeedSmart app or try one of the online training courses through DiversityEra – all located at www.weedsmart.org.au.

While WeedSmart is predominantly aimed at farmers, AHRI continues to publish more technical information for field scientists and agronomists through its own blog and website.

“We have platforms to cater for everyone, with our webinars also attracting international speakers and tapping into a global network,” adds Ms Mayer.

WeedSmart roadshow

In addition to the significant online presence, “WeedSmart Week” sees the initiative take to the road once every year, moving to a different state each time.

This allows applied researchers to showcase the latest findings and advice and pulls in the most progressive farmers within the region to discuss their experiences of weed control and herbicide resistance management.

Promoting diversity has been at the heart of AHRI and WeedSmart, both in chemical and non-chemical approaches to weed control, and Ms Mayer says it is having an impact.

About 40% of farms across Australia are now practicing some sort of harvest weed seed control – catching and destroying weed seeds at harvest – to reduce seed return. This increases to 65% when considering Western Australia alone.

There is also evidence to suggest that all of the “Big 6” are being taken up, including mixing and maintaining herbicide rates and introducing more diverse rotations.

“AHRI and WeedSmart are completely unique, as you have just one stewardship platform that gives a single voice across the industry covering cereals, pulses and cotton,” Ms Mayer says.

“Why recycle the same message? It also adds credibility to the messages as it is aligned with a university research group and completely independent.”

AHRI director Stephen Powles, an internationally renowned weed resistance expert, adds the UK could certainly learn from the experiences in Australia.

“When I’ve been [to the UK], my only frustration has been the communications with farmers and the ad hoc nature of it. Devising a proper, more focused strategy could really help.”