To assist growers and their advisers in combating Feathertop Rhodes grass (FTR), an Integrated Weed Management (IWM) manual has been published on the weed.
Once common only on roadsides and fence lines, FTR is now more widespread due to the shift in cropping systems to minimum or zero tillage, as has been the case with many emerging problem weeds in non-traditional areas.
“Feathertop Rhodes grass is now a formidable challenge to current zero till farming systems across QLD and NSW,” said CQGS extension agronomist Darren Aisthorpe from DAF QLD.
A reliance on knockdown herbicides (glyphosate) has failed to manage the weed—field observations show that since 2011 the efficacy of glyphosate on FTR has continued to decline.
“For many growers the battle against FTR has long been fought with knockdown herbicides and slowly but surely that battle is being lost,” Mr Aisthorpe said.
The threat of resistance and selection for increased tolerance in weed species means that knockdown herbicides can no longer be automatically considered the preferred option for grass weed management. Weeds like FTR now require a much broader suite of strategies, used in combination, to help slow the inevitable transition to becoming herbicide tolerant.
“What we need to consider is giving up our reliance on ineffective knockdown strategies and moving instead to a multi-pronged strategy that helps stop seed set and exhausts the seed bank,” said Mr Aisthorpe.
Moonie grower, Neville Boland, cultivates about 4000 hectares a year near Goodiwindi, and said the advent of herbicide resistance in weeds—in particular fleabane, FTR and barnyard grass—has impacted his crop rotation and soil management.
“There’s a lot of FTR around our property,” he said. “I remember seeing it occasionally in the 80s around the old oil well sites and gravel roads on my dad’s place. It’s really growing everywhere, including in my house lawn. I think it’s here to stay, but that doesn’t mean it can’t be controlled.”
Mr Boland uses a flexible rotation and an opportunity cropping system, but with the increase of herbicide resistance in weeds, he has had to turn to more residual herbicides and strategic tillage.
“Careful, minimum tillage, without bashing the soils about, means it is possible to manage FTR,” he said. “Tillage is cheaper than herbicide, and it gives you more robust control. We till, for instance, when there’s no stubble, and we do it in one pass using rotary harrows behind a cultivator. This keeps the operation one pass rather than needing a second pass to sort out lumps and clods left by finger harrows.”
“By thinking strategically, I’ve managed to control my FTR problem.”
FTR is often the first species to germinate after rainfall, and the plants stress very easily and quickly (often before other species in the paddock), making herbicide uptake difficult.
“The FTR seedbank can be fully depleted in 12–18 months, so with a careful use of weed-seed control, crop rotation, strategic tillage and techniques such as burning on top of traditional herbicide control, growers stand a good chance of being able to remove the weed successfully,” Mr Aisthorpe said.
“Through a well-planned weed management strategy it can be targeted effectively, and this is what the new manual aims to help growers achieve in the northern region.”
The FTR manual offers an overview of FTR and its biology as well as practical advice on all aspects of FTR management. Content is based on the latest FTR research findings.
The manual includes advice on:
- control tactics, such as post-emergent and residual herbicide options
- the use of crop rotations
- chemical groups to include in a management program
- how to implement an effective integrated control strategy.
“Growers, can use simple techniques like broadleaf crops in rotation with cereals to broaden the residual control and knockdown options,” said Mr Aisthorpe.
“More fundamental ideas, like using narrow rows and uniform plant populations, will also increase crop competitiveness.”
This project was co-funded by GRDC and Department of Agriculture and Fisheries (DAF) QLD.
Department of Agriculture and Fisheries (DAF)
Ph: 0427 015 600
GRDC Project Code