Oat production in Australia has been constrained partly due to the lack of weed management tools. This is because oats have been considered a minor crop by many of the chemical registrants due to the relatively small area of production, making the registration of crop protection chemicals for pest, disease and weed control more challenging.

However, through several industry collaborations, this is changing and began with the registration of Nufarm TriflurX®, a Group 3 mode of action pre-emergent herbicide for use with oats, in early 2022.

“Grass weed control and lack of chemical options in oat crops compared to the other major cereals have been significant and ongoing issues for oat growers,” says GRDC manager for chemical regulation Gordon Cumming.

The registration of Nufarm TriflurX® was achieved through the collaborative efforts of GRDC, the Western Australian Department of Primary Industries and Regional Development, ConsultAg and the Grain Industry Association of WA.

Three years of collaboration

“The registration of Nufarm TriflurX® for oats followed three years of cross-agency collaborative work that covered field trials involving both crop safety and residue studies to generate the required data for the Australian Pesticides and Veterinary Medicines Authority (APVMA) registration submission,” Mr Cumming says.

AgriFutures Australia, supported by the Agricultural and Veterinary Access Grant Program funding through the federal Department of Agriculture, Fisheries and Forestry, undertook the crop safety studies for oaten hay production, while GRDC invested in the required grain residue studies that included hay and forage samples.

Field trials and data generation are only one part of the process. The label is owned by the chemical registrant, and they are required to prepare and make the submission to the APVMA. Nufarm provided the regulatory expertise to compile the submission based on its TriflurX® label, which is now the only product to carry this registration for oats.

GRDC is now starting the process with another pre-emergent herbicide for oat growers, prosulfocarb, a Group 15 herbicide.

Annual ryegrass is a particular target for this different mode of action herbicide. Its proven ability to develop resistance to herbicides means we must continually change up the means with which we control this weed species. We need additional tools in the toolbox for oats.

“Generating the required data to support the registration of prosulfocarb for oats will take a similar time to the TriflurX® registration and, if successful, is likely to be available for growers in 2025.”

Herbicide-tolerant oats

Oats have a reputation for vigorous early growth that can suppress weeds and also a long history in being used to clean up problem weeds by making hay. But as farming systems change, new tools are required.

The development of imidazoline-tolerant crop varieties has provided significant farming systems advantages – both by the application of imidazoline herbicides to control a broad spectrum of grass and broadleaf weeds, including weeds that are closely related to the crop itself, and the use of imidazoline-tolerant crops where there may be imidazoline soil residue concerns from previous crops.

Oats have now been equipped with imidazoline tolerance with the registration of the world’s first tolerant oat, Kingbale in early 2021, the culmination of three years of research and development between Australian companies Nufarm, InterGrain and Grains Innovation Australia (GIA). The plant breeding work was undertaken by Dr Michael Materne from GIA.

Together with GIA and Nufarm, InterGrain released a second imidazoline-tolerant oaten hay variety, Archer in August 2022. Nufarm Sentry® herbicide is currently registered for pre-planting incorporation by seeding for hay and seed production in Kingbale and Archer.

More information: Gordon Cumming, gordon.cumming@grdc.com.au