An opportunity exists for WA’s southern grainbelt growers to use harvest residues from annual ryegrass ergot grading to test weed seeds for herbicide resistance (or susceptibility).
Australian Glyphosate Sustainability Working Group (AGSWG) executive officer, Andrew Storrie, said late spring rainfall of more than 200mm received by many southern grainbelt farms last year created widespread annual ryegrass ergot problems at harvest.
He said strict grain receival standards for ergot, which is a fungal disease contaminating cereals, forced many growers to grade their grain before delivery.
“This has resulted in big remnant heaps of ergot and weed seeds - including annual ryegrass, brome grass and wild radish - now sitting in many paddocks,” he said.
“This problem may just provide a real boon for growers if it is used as an opportunity to test the weed seeds for herbicide susceptibility before the 2015 growing season.”
Testing weed seeds can save time and money and paves the way for fine-tuning weed management strategies to ensure weeds can be controlled and herbicide options are preserved.
Mr Storrie said currently only a small percentage of grain growers tested weed seeds for herbicide susceptibility, but the gradings from annual ryegrass ergot in 2014 provided a readily available source of seeds to see which herbicides would be effective this year.
He said the AGSWG, which is supported by the Grains Research and Development Corporation (GRDC), had found that one of the reasons for low levels of herbicide susceptibility testing to date was that growers were too busy to collect samples before or at harvest.
“So this is a chance not to be missed,” he said.
Mr Storrie said when organising testing, it was best to start with the most commonly used herbicides on the farm.
“Further advice about which herbicides to test for should be assessed in conjunction with the farm adviser and/or the testing service that you plan to use,” he said.
“Knowing if your herbicides still work is particularly important if you are a fan of dry seeding.
“When dry seeding, if your post-emergent herbicides don’t work, you had better make sure you are sowing into weed-free paddocks.”
Surveys in WA during the past two years have shown that more than 40 per cent of paddocks tested for herbicide resistance have some level of glyphosate resistance, according to Mr Storrie.
“This indicates we are close to a tipping point - when glyphosate resistance is likely to start becoming obvious in cropping paddocks,” he said.
“Knowledge is power, so now is the time to find out what you are dealing with.”
The two weed seed testing services available in Australia are provided by Peter Boutsalis’ Plant Science Consulting (PSC), in South Australia, and John Broster at Charles Sturt University (CSU), in NSW.
They take mature weed seeds collected during or after harvest, grow these out in controlled environments from December to February, treat the weed plants with the herbicide/s requested by the grower and then assess survival.
More information about these services is available at:
It is recommended samples are sent before the end of January (in paper bags/envelopes - not plastic) so results are available before the beginning of the cropping season.
The AGSWG website has a range of information about glyphosate resistance, including a register of glyphosate resistant weed populations and guides and links for management of glyphosate resistance in a range of crops and management situations.
For more information, go to: www.glyphosateresistance.org.au
For information about herbicide sustainability, visit GRDC’s Integrated Weed Management hub at: www.grdc.com.au/Resources/IWMhub and the WeedSmart information hub at: www.weedsmart.org.au
Caption: Many southern WA grainbelt growers were grading harvested grain before delivery this year, creating an opportunity to now test weed seeds in the residue for herbicide resistance/susceptibility. PHOTO: Andrew Storrie, AGSWG.
Andrew Storrie, AGSWG
08 9842 3598, 0428 423 577
Melissa Williams, Cox Inall Communications
0428 884 414
Paddock Practices Time to test the susceptibility of escapee weed seeds: www.grdc.com.au/PP-TestSusceptibilityofEscapeeWeedSeeds
GRDC IWM hub: www.grdc.com.au/Resources/IWMhub
WeedSmart information hub: www.weedsmart.org.au
Australian Glyphosate Sustainability Working Group: www.glyphosateresistance.org.au
Australian Herbicide Resistance Initiative (AHRI): www.ahri.uwa.edu.au
Driving Agronomy: Test your weeds: www.grdc.com.au/DAPodcasts-TestYourWeeds
GRDC Herbicide Resistance Fact Sheet: www.grdc.com.au/GRDC-FS-HerbicideResistance
GRDC Project Code