Pre-harvest canola spray allowed

Headshot of Jenne Brammer
Jenne BrammerThe West Australian

Farmers can for the first time apply glyphosate to canola crops before harvest, following the Australian Pesticides and Veterinary Medicine Authority's approval of Nufarm's weedmaster DST as the only registered glyphosate product for this use.

Until now, there has been no product registered for late season application to help reduce the development of weed seed set into the following season.

Grains Industry Association of WA chairman Jon Slee said this was an important registration for the industry and gave growers another "tool in the toolbox" for their weed management program.

"Control of radish and ryegrass seed set late in the season has always been a challenge and anything that can help to reduce the carryover of seed into the following season is greatly welcomed," he said.

The registration applies to Nufarm's weedmaster DST glyphosate, but Mr Slee expects registration of competitor products will follow.

As part of the approved registration, growers will be able to apply weedmaster DST, a 470g/L glyphosate, after 20 per cent canola seed colour change or under the cutterbar at time of windrowing.

It can be applied at this time in all canola systems including Triazine Tolerant, Clearfield, Roundup Ready and conventional varieties.

The new registration, which was part of a three-year, joint-funded program between Nufarm and the GRDC, is considered crucial by many in the industry to control annual weeds, such as ryegrass.

Trial results, as part of the registration process, showed that an application of weedmaster DST on canola at windrowing reduced annual ryegrass seed production by more than 70 per cent, with similar results seen when applied to standing crops before harvest.

Nufarm research and development manager Andrew Wells said this registration would give growers more options to help reduce the weed seed set and the potential for herbicide resistance developing.

"The issue of weed seed set is particularly important when considering weeds like annual ryegrass and wild radish, which are both capable of producing thousands of weed seeds per plant and can be spread readily," he said.

"An application of weedmaster DST prior to seed formation in ryegrass significantly reduces this from occurring."

Mr Wells said extensive trial data from Nufarm also showed there were no negative effects on canola crop yield or oil content and when weedmaster DST was applied according to the product label, there were no concerns regarding maximum residue levels for export grain.

Cuballing farmer Bill O'Neill described the development as highly positive, particularly for growers such as himself who run continuous cropping programs.

This year he planted 320ha of canola as part of his broader cropping program.

"Until now there has not really been a legal late season option for controlling weeds in canola," he said.

"Now this will form part of our weed control strategy and will spray at the same time as swathing.

"The end result should be a significant reduction in weeds next year and a reduced likelihood of herbicide resistance."

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