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Hybrid canola out-competes weeds

Canola production is predicted to rise by 30 per cent in 2017 with over 98 per cent of farmers growing herbicide-tolerant canola cultivars. However, Australia has been lagging behind other producing countries in the uptake of hybrid cultivars that offer higher yield and more options for effective weed suppression in crop rotations.

Researchers at Charles Sturt University compared the competitive ability of 16 genotypes – hybrid and open-pollinated cultivars – and found the most competitive cultivars reduced weed biomass at flowering by a huge 50 per cent, significantly reducing the amount of weed seed added to the seed bank. A similar trial, conducted by researchers at the University of Adelaide, found that annual ryegrass plants that survived pre-emergent herbicide produced more than twice as much seed in open-pollinated TT canola than in the hybrid Clearfield canola.

Although the triazine-tolerance (TT) trait is known to confer a yield penalty of up to 10–20 per cent, this technology is currently adopted on 65–70 per cent of the national canola area. The vast majority of TT canola cultivars are open-pollinated while most Clearfield (CL) and Roundup-Ready (RR) cultivars are hybrids.

Kevin Morthorpe, *GenTech Seeds’ Canola Business Lead and Product Stewardship Manager hopes that the new hybrids available in 2017 will encourage growers to continue to shift away from the less competitive, open-pollinated cultivars to take advantage of the more vigorous, higher biomass and higher yielding hybrids.

Kevin Morthorpe, GenTech Seeds, is concerned that canola growers are relying too heavily on the less competitive triazine-tolerant (TT) cultivars and missing out on the higher yield and better weed control benefits of hybrid canola systems.

Kevin Morthorpe, GenTech Seeds, is concerned that canola growers are relying too heavily on the less competitive triazine-tolerant (TT) cultivars and missing out on the higher yield and better weed control benefits of hybrid canola systems.

“Crop competition is one of the best non-herbicide weed management tools available and the new hybrids are offering growers real bang for their buck in terms of extra yield and driving down the weed seed bank,” he said. “These benefits for the grower far out-weigh the additional cost of hybrid canola seed. The yield advantage achieved through hybrid vigour only occurs in the F1 generation so retaining seed for future use is counter-productive.”

Mr Morthorpe said enhanced crop competitiveness in hybrid crops is best achieved through attention to crop nutrition to optimise early growth and harvestable yield. “Research studies in canola have not shown a plateauing in crop yield response to higher nutrient input as is often observed in the ‘haying off’ of cereals at higher nutrient rates,” he said.

The suppression of weed growth is closely tied to strong root development, increased crop biomass and improved early crop vigour. Field trails also indicate that some cultivars have an allelopathetic effect on weeds. Speedy emergence, early vigour, rapid ground cover and height are all important characteristics of the most competitive hybrids.

Hybrid growers are also able to strategically integrate alternate herbicide modes of action and reduce reliance on Group A herbicide applications in the canola phase.

Hybrid canola suppresses weed biomass and seed production by about 50 percent compared to open-pollinated triazine-tolerant (TT) canola cultivars due to the speedy emergence, early vigour, rapid ground cover and height characteristics of the most competitive hybrids.

Hybrid canola suppresses weed biomass and seed production by about 50 percent compared to open-pollinated triazine-tolerant (TT) canola cultivars due to the speedy emergence, early vigour, rapid ground cover and height characteristics of the most competitive hybrids.

Herbicide Tolerant Canola Stewardship Guide

GenTech Seeds, an industry partner of WeedSmart, is committed to product stewardship. Their recently-published ‘Herbicide Tolerant Canola Stewardship Guide’ outlines the sustainable use pattern for all herbicide tolerant cultivars. Mr Morthorpe said the stewardship guide is a practical approach to integrated weed management within the canola phase and fully supports the The Big 6.

“In triazine-tolerant crops the main points are to carefully manage the lower crop vigour of TT canola, monitor triazine herbicide carryover risk for crop rotational planning and always adhere to mandatory application practices for triazine herbicides (atrazine, simazine) set by industry in cooperation with government,” he said.

“To protect Clearfield technology, the whole farm rotation plan needs to limit the use of ALS-inhibiting herbicides to no more than two out of four years. Avoid crop injury by using quality assured, first generation seed and monitor the carry over risk of imidazoline herbicide on future crop rotation options.”

“Planting Roundup-Ready hybrids requires a critical assessment of the use of glyphosate as a stand-alone knockdown for non-crop application such as fencelines and over-reliance across the farming system. A whole-farm strategy needs to be in place to manage glyphosate resistant weed populations and to control RR crop volunteers in the fallow phase.”

The general principles for weed control and herbicide use apply for all herbicide tolerant canola systems, including using a combination of registered pre-emergent and post-emergent herbicides, always following the label directions of use and pro-actively implementing diverse weed management tactics across the farming system.

Post-emergent herbicide applications must target small weeds (2–3 leaf ryegrass and/or 2–3 cm diameter broadleaf leaves) early in the crop’s development and selective herbicide application should occur before elongation of canola plants (BBCH 16).

“When it comes to managing herbicide resistance and protecting the plant breeding technologies available, the key is to have low weed numbers entering and leaving the canola phase,” he said. “To achieve this, growers can rotate the crop types, herbicide tolerance technologies and herbicide modes of action used across the crop rotation to broad the opportunities to implement a diverse range of weed management tactics to prevent weed seed set and to implement harvest weed seed control to collect any seed present at harvest.”

The ‘Herbicide Tolerant Canola Stewardship Guide’ includes a detailed integrated weed management (IWM) strategy that highlights herbicide and non-herbicide tactics growers can employ in the pre-planting, in-crop, harvest and post-harvest phases to control weeds and reduce weed seed set.

This Guide also promotes recommended stewardship practices along the supply chain to ensure responsible use of new technologies, predictable market access and builds on Australia’s competitive edge in international oilseed markets.

*GenTech Seeds is the exclusive producer distributor of Pioneer® brand products in Australia.

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What to expect at WeedSmart Week 2021

Big 6 at WeedSmart Week 2021 – Double knock to protect glyphosate
The WeedSmart Forum is set for Tuesday 17 August, 2021 at the Civic Centre in Esperance WA. The program features growers, agronomists and researchers discussing ways to use the BIG 6 to beat crop weeds. You can register for the 3-day WeedSmart Week event here.
Greg Warren from Farm and General in Esperance will be sharing his thoughts on the control of weeds like summer-germinating ryegrass, marshmallow, fleabane and portulaca.
He says the growers around Esperance are tackling glyphosate resistance in annual ryegrass, along with brome and barley grass and other emerging weeds using a range of integrated control tactics. The double knock plays a key role in preserving glyphosate (and soil moisture) and providing a clean seed bed for planting crops.

 
Big 6 at WeedSmart Week 2021 – Increase crop competition
WeedSmart Week 2021 is set for Tuesday 17 to Thursday 19 August, 2021 in and around Esperance WA. The last two days feature local growers hosting visits to their farms and discussing how they use the BIG 6 to beat crop weeds. You can register for the 3-day WeedSmart Week event here.
One of the farms hosting a visit during WeedSmart Week is Warrakirri’s 12,800 cropping operation at Condingup. Farm manager Con Murphy has implemented a variety of tactics to combat their main weeds – annual ryegrass and wild radish. Since 2015 the farm has undergone an intensive soil amelioration program to improve the drainage and ameliorate the sandy soils across the farm.
Con says the benefits have been seen in better germination and establishment that sets their cereal, pulse and canola crops up to compete strongly with weeds. There is also a benefit at the end of the season where rain in August or September enters the soil profile without causing waterlogging, and providing a better finish for their crops.
Since 2016-17 about 80% of the farm has been ripped and a portion has been ripped 2 or 3 times because the sandy soils tend to slump after substantial rainfall events, recreating the hardpan.
Con will be showing the WeedSmart tour group how their ripping, drainage, liming and spading program has helped grow more crop and less weeds!
Listen to the podcast with Warrakirri’s Con Murphy talking about the impact of improved drainage on crop competition

Big 6 at WeedSmart Week 2021 – Implement harvest weed seed control
The WeedSmart Week machinery display is set for Wednesday 18 August, 2021 at Dave Campbell’s shed near Esperance WA. The 3-day WeedSmart Week program features growers, agronomists and researchers discussing ways to use the BIG 6 to beat crop weeds. You can register for the 3-day WeedSmart Week event here.
We’ve saved the harvest weed seed control discussion for the machinery session on Wednesday 18 August. Ben White from Kondinin Group will host the machinery session with spray and harvesting gear on display including impact mills from Seed Terminator, Redekop and iHSD (both hydraulic and belt-driven), Emar chaff deck, and spray technologies including Goldacres’ G6 Crop Cruiser series 2, and weed detection technologies using drones and weed identifying cameras (green on green).
Ben White, Kondinin Group (Photo: Melissa Powell, courtesy of GRDC)
Growers doing the WeedSmart Big 6
WeedSmart Week 2021 is set for Tuesday 17 to Thursday 19 August, 2021 in and around Esperance WA. The last two days feature local growers hosting visits to their farms and discussing how they use the BIG 6 to beat crop weeds. You can register for the 3-day WeedSmart Week event here.
One of the growers who will open up their farm for a visit is Adrian Perks who farms at Condingup, 70 km north-east of Esperance. Adrian runs a continuous cropping program on his 4300 ha property, growing canola, wheat, barley, faba beans and lupins. This diverse rotation allows him to mix and rotate both chemical and non-chemical weed control tactics. Over half of Adrian’s farm is sandplain, on which he has implemented a soil amelioration program to address non-wetting to increase the competitiveness of his crops. He currently uses chaff decks for harvest weed seed control and is introducing an impact mill this season. Adrian monitors the tramtracks for weed growth and if he feels the weed pressure is too high, he uses a shielded sprayer to reduce seed set. The bus tour will include four farm visits and a machinery display.
Listen to Adrian on the Regional Update podcast.
Adrian Perkins, Condingup WA
 

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WeedSmart agronomist set to tackle high rainfall zone weeds

Every locality has its own spectrum of weeds, and growers face different opportunities and challenges regarding the control tactics they can employ.
The WeedSmart Big 6 approach is a practical way to ensure that an integrated weed management program is put in place that disrupts weed seed production and the evolution of herbicide resistance.
Commencing in January 2021, Jana Dixon has joined the WeedSmart team of extension agronomists, with a focus on applying the Big 6 to manage weeds in the high rainfall cropping systems of southern Australia – from Esperance in WA to south-eastern SA, Tasmania and south-western Victoria.
Jana will add to the dedicated and experienced extension agronomists on the WeedSmart team with Peter Newman in the Western region, Chris Davey in the South, Greg and Kirrily Condon in the East and Paul McIntosh in the North.
Jana Dixon has joined the WeedSmart team of extension agronomists, with a focus on applying the Big 6 to manage weeds in the high rainfall cropping systems of southern Australia – from Esperance in WA to south-eastern SA, Tasmania and south-western Victoria.
Jana hails from the Mid North of SA, and began working at Pinion Advisory (previously Rural Directions) while she was studying agriculture at the University of Adelaide. She has been employed full-time at Pinion Advisory since January 2019 as an agribusiness consultant, based in Clare, and spends most of her time delivering agronomy and farm business advice to clients from a wide range of cropping regions in South Australia.
Pinion Advisory is a foundation WeedSmart sponsor and Jana has been involved in two WeedSmart Week events already – the first as a participant and grower group organiser at the Horsham event in 2019 and then as the local organiser for WeedSmart Week 2020 in Clare.
In welcoming her to the WeedSmart team, program manager Lisa Mayer says Jana brings energy, commitment and insight to deliver communications focussed on the southern region’s high rainfall regions.
“Growers in the southern high rainfall zones are facing some serious issues with herbicide resistance influencing their farming decisions,” says Ms Mayer. “Jana will be engaging with agronomists, growers and researchers in each of the distinct high rainfall zones to understand the complexities and look for practical ways to apply the WeedSmart Big 6 in various cropping scenarios.”
“We plan to deliver WeedSmart Week in Esperance, part of Western Australia’s high rainfall cropping zone, in August 2021 and Jana will play a key role in the planning and delivering of our annual 3-day flagship event.”
Jana says her experience with the WeedSmart program has been very positive and she has been particularly impressed with the support the program has from all sectors of the grains industry.
Newly appointed WeedSmart extension agronomist, Jana Dixon (green cap) leading discussions with farm visit host, Ben Marshman, Owen SA, and growers and agronomists attending WeedSmart Week 2020 in Clare.
“I have spoken to many growers and agronomists who have found real value in the information that the WeedSmart program delivers,” she says. “For many it is as much about considering another operator’s philosophy on dealing with weeds, and taking a fresh look at their own systems, rather than just learning about a new tactic or the traits of a new herbicide in isolation from the big picture.”
She says the high calibre of industry people who contribute their time and expertise to the program is testament to the value WeedSmart has to agribusiness, growers, agronomists and researchers alike.
In taking on the responsibility for delivering information tailored for the high rainfall zones Jana says she is pleased to have an extensive network of contacts through Pinion Advisory, with offices in a number of high rainfall areas to provide easy access to local agronomists and growers. She is also aware that there are major differences in weed spectrums and farming systems in each high rainfall zone and plans to take full advantage of the opportunity this role presents to expand her understanding of different approaches to weed management.
“The long and favourable growing season and the associated prolonged periods of weed germination, is a key factor that I see potentially impacting on a grower’s weed management strategies in these regions,” she says. “On the other hand, access to highly diverse rotations and a focus on crop competition are two strategies that can play an important role in achieving excellent weed management in these regions.”
“I am keen to engage with anyone working and farming in the high rainfall zones to build my knowledge and understanding,” she says. “And to create opportunities to develop and extend the WeedSmart Big 6 strategies, both herbicide and non-herbicide, that work in each area and in different situations.”
WeedSmart is the industry voice delivering science-backed weed control solutions with support from the Grains Research and Development Corporation (GRDC), major herbicide, machinery and seed companies, and university and government research partners, all of whom have a stake in sustainable farming systems.
You an follow Jana on Twitter and keep up to date with the HRZ here.

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Never cut the herbicide application rate

Scientific studies have demonstrated that resistance can rapidly evolve in weeds subjected to low doses of herbicide. Some weeds can develop resistance within a few generations.
Full rates when mixing herbicides too!
When mixing herbicides it is important that each product is still applied at the full label rate to ensure high mortality.
Applying different chemicals in one mix can provide an additive advantage. It is important to understand the mode of action of each herbicide on the plant when preparing a herbicide mix. This is just as important for pre-emergent grass weed mixes as it is for post-emergent mixes aimed at broadleaf weed control. ALWAYS READ THE LABEL.
Surrounding weed seeds with a combination of pre-emergent herbicides with different modes of action can give a high level of control and help extend the useful life of all the chemicals used. The high level of control must be supported with additional control measures for all survivors. All products with different modes of action must be applied at full label rates for this to be an effective strategy.

 
Mixing two chemicals with the same mode of action can achieve some additional efficacy, however, the mix should deliver the combined full rate to ensure a lethal dose. The amount of stubble present and crop safety are all important considerations when mixing chemicals. For example, when using a tank mix of Avadex® and trifluralin to control ryegrass in wheat, the rates used will vary depending on the sowing system and level of stubble retention. Be sure to get good advice.
Many herbicides on the market are a combination of two or more modes of action within the one product. These products must be applied at the full label rate to be effective. Having dual action does not negate the need to change herbicide products and rotate modes of action. Repeated use of any single strategy will reduce the effectiveness of that strategy over time.
 

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