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What can I do to control large FTR grass in fallow?

Feathertop Rhodes grass (FTR) is a major weed in chemical fallows in Australia, and is notoriously hard to kill with glyphosate.
Bhagirath Chauhan, professor at the University of Queensland’s Centre for Crop Science, says some other herbicide control measures have potential to manage large FTR plants (40 to 50 leaf stage) that have escaped earlier treatment.
Professor Bhagirath Chauhan says there are some tank mixes and herbicide sequences that growers could deploy to help manage FTR and stop seed set.
“Feathertop Rhodes grass is an aggressive weed that can establish in bare fallow situations and produce a large quantitiy of seed if left uncontrolled,” he says. “Several biotypes of this species are resistant to glyphosate and can also survive a double knock of glyphosate followed by paraquat, particularly once the weed is larger than 4 to 5 leaf stage.”
To give growers more options, a study was conducted to assess the potential of other herbicides and use patterns that can control large feathertop Rhodes plants or stop seed set.   
Alternative herbicide options are available to help manage large FTR and reduce seed set in fallow.
“An integrated approach is essential to controlling feathertop Rhodes grass,” says Bhagirath. “In applying the WeedSmart Big 6 to FTR in a bare fallow situation we have identified some tank mix and herbicide sequences that growers could deploy to help manage this difficult weed and stop seed set.”
Can anything be done to improve the efficacy of glyphosate or the double knock against large FTR plants?
In brief: Adjuvants did not improve glyphosate efficacy on mature (40 to 50 leaf) FTR plants. In glyphosate resistant populations, the second knock product is doing the heavy lifting when applied to large (8 to 10 leaf) FTR plants.
The details: None of the commercially available adjuvants improved the efficacy of glyphosate (740 g a.e. per ha) as a single product application on FTR at the 40 to 50 leaf stage. All the plants survived and produced seed after being treated with glyphosate, indicating that the population used in the study was resistant to glyphosate at this rate and weed growth stage.
Glyphosate and the double knock tactic can often provide good control of resistant FTR plants if the herbicide is applied when the plants are small and actively growing.
The traditional double knock of glyphosate (Group 9 [M]) or glyphosate + 2,4-D, followed by paraquat (Group 22 [L]) or glufosinate (Group 10 [N]), applied to older FTR plants (8-10 leaf) achieved increased phytotoxicity through improved mortality, reduced biomass or fewer seed panicles.
However, the double knock was no better than using paraquat or glufosinate alone when applied to 8 to 10 leaf FTR plants. FTR is not listed on glufosinate labels in Australia but is used to control other weeds in fallow situations at the rate (750 g a.i. per ha) tested in this study. For best results, glufosinate needs to be applied in warm, humid conditions, which is not a common scenario for summer fallow situations.
Rate response (0, 187.5, 375 and 750 g a.i. per ha) to glufosinate applied to large FTR plants.
Are clethodim or haloxyfop suitable alternative herbicides to treat large, glyphosate resistant FTR plants?
In brief: Possibly. Excellent results were achieved in pot trials conducted in an open environment, but will be more difficult to achieve in the field.
The details: Clethodim and haloxyfop were tested on FTR plants at the 24 to 28 leaf stage. Clethodim is registered for use against FTR in a number of summer crops, but without any crop competition many FTR plants survived the registered rate (90 g a.i. per ha), although weed biomass and seed production was severely curtailed.
Haloxyfop efficacy against FTR at this growth stage was 100 per cent at the registered rate of 80 g a.i. per ha.
A combination of these two treatments also resulted in 100 per cent control. The effective use of these two herbicides (both Group 1 [A]) relies on excellent coverage and application when the plants are actively growing. This is difficult to achieve in field conditions, which is why the label recommendations are typically for younger weeds.
A combination of clethodim and haloxyfop can provide good control of large feathertop Rhodes plant and curtail seed production.
These herbicides are known to readily select for resistant biotypes so when applied in a chemical fallow situation (with no competition), it is necessary to target small weeds with robust application rates and to apply a second knock with a contact herbicide, such as paraquat. 
Did you find any new and exciting prospects for controlling mature FTR plants?
In brief: Yes, it seems that there is a truly synergistic effect when isoxaflutole (Group 27 [H]; e.g. Balance) is mixed with paraquat.
The details: Neither of these herbicides provided useful control of FTR at the 40 to 50 leaf stage when applied individually. When mixed together, these herbicides achieved a higher level of weed mortality and prevented panicle production. For example, a tank mixture of isoxaflutole 75 g a.i. per ha, with paraquat 600 g a.i. per ha, resulted in 92 per cent FTR mortality and no panicle production.
Even at a paraquat rate of 300 g a.i. per ha mixed with isoxaflutole 75 g a.i. per ha, only 17 per cent of the large FTR plants survived when the mixture was applied to both the plant and the nearby soil – allowing uptake through both the leaves and the roots.
The benefit of this mixture may be reduced if the weed patch is dense, potentially reducing the amount of the isoxaflutole that reaches the soil. Even the prevention of seed set in large FTR plants is of significant value in managing the seed bank of this invasive weed, as FTR seed remains viable for less than 12 months.
Such a use pattern is not currently specified on product labels, although both products are registered for weed control in fallow situations.  
Web resources
Read the research paper.


Testing informs herbicide choice

Buying a new property brings with it a number of unknowns and it can take some time for the new owners to become familiar with the soils, the terrain and the weeds.
When the Birch family of ‘Catalina Farms’, Coorow, WA purchased a neighbouring property, historic ‘Koobabbie’, they had reason to expect that herbicide resistance would be less of a problem because there had been limited use of herbicides on ‘Koobabbie’ in its 114 history of farming.
Daniel Birch, who farms with his wife Jen, parents Rod and Shelley, and long-term team member, Justin Passamani, says the purchase conveniently coincided with the opportunity to be involved with independent herbicide resistance testing in 2020.
“The testing was arranged through the Liebe Group and conducted at the Australian Herbicide Resistance Initiative,” he says. “We were keen to test some theories we had about resistance status of weeds on Catalina and also to get some baseline information about Koobabbie to help us plan our herbicide program.”
Daniel Birch of ‘Catalina Farms’, Coorow, WA says the big take home message from recent herbicide resistance testing was the power of mode of action mixtures.
The testing revealed a number of things that surprised the Birches. To start with, they found there was Group 2 [B] resistant ryegrass in paddocks on Koobabbie that had no history of Group 2 herbicide use.
“This demonstrated just how easy it is for herbicide resistance to move in seed or hay, or on machinery,” says Daniel. “Obviously we can use this information to avoid using chemistry that we know has little to no efficacy on ryegrass.”
“The other major finding was that Group 12 [F] resistance in wild radish was much higher than we expected across the farm,” he says.
This has led the Birches to include more premium products in their program to target resistant ryegrass and wild radish, and drive down the weed seed bank as quickly as possible. On the flip side, they also discovered that they can save money by using trifluralin at lower rates in seasons with good growing conditions, where there is less need for a long residual effect.
“In those years where the crop gets off to a good start, the crop competition effect kicks in early to suppress weeds,” says Daniel.
By taking on board the resistance testing results from weed seed samples collected across the state, Daniel was reassured by the fact that the resistance issues they faced were essentially the same as other growers.
“The big take home message for us was the power of mode of action mixtures,” he says. “From the overall survey results across Australia, the resistance frequency to stand-alone pre-emergence herbicides ranged from 10 to 34 per cent, yet resistance to herbicide mixtures ranged from 0 to 6 per cent.”
Armed with knowledge about the resistance profile of their weeds, the Birches are combining some older chemistry with newer, premium herbicides for maximum effect.
The AHRI resistance testing program is led by Dr Roberto Busi. In 2019, annual ryegrass seed samples from 298 farms were submitted, representing 579 populations from four states in Australia, and these were tested for resistance to 21 herbicides applied at the recommended rate – 12 standalone and nine two-way mixtures.
In total, 15 876 individual resistance tests were conducted to screen two million seeds against registered herbicides and herbicide mixtures at the recommended label rate.
Dr Busi says the mixtures that growers can confidently incorporate in their annual ryegrass program are trifluralin + Sakura mix, Luximax + triallate, and clethodim + butroxydim.
“When applied at full rate for each component, these mixtures can achieve a better outcome than the same herbicides applied as stand-alone treatments against annual ryegrass with known resistance,” he says.
For wild radish, 200 samples were tested over a period of two years and resistance to Groups 2 [B], 4 [I] and 12 [F] were all over 50 per cent resistant. At 70 per cent resistant, Group 2 [B] herbicides should probably be dropped from most wild radish herbicide programs and Group 4 [I] is under threat.
“In 2021, we found that mixing Group 12 [F] with Group 6 [C] herbicide bromoxynil vastly improved control of wild radish,” he says. “From 51 per cent resistant to Group 12 [F] down to less than 15 per cent of samples resistant to the 12 [F] plus 6 [C] mixture.”
“It is important to emphasise that herbicide resistance testing is conducted on small, actively growing weed seedlings in a glasshouse environment,” says Roberto. “In the field, spray failures can easily occur, even in susceptible weed populations, if the herbicide is applied under the wrong conditions or to plants that are too large or stressed. This is particularly true for wild radish.”
AHRI Podcast: Interview with Daniel Birch about herbicide testing
AHRI Insight: Mixtures rock
Herbicide testing options


Safe sorghum planting while controlling weeds

Pre-emergent herbicide, metolacholor and S-metolachlor, have been used in Australia primarily to control grass weeds for over 40 years. To date, no instances of resistance to this active ingredient have been documented in Australia and even internationally the few cases of resistance are in broadleaf weeds only. Resistance in northern summer grasses is probably low at present.
Syngenta’s field biology manager, Rob Battaglia, says some recent changes to the label use patterns and the launch of a new seed safener product will further expand the usefulness of S-metolachlor products, such as Dual Gold® and Primextra Gold®, in summer crops while protecting sorghum seedlings from herbicide damage.
Syngenta’s field biology manager, Rob Battaglia, says the new use patterns for Dual Gold® in sorghum, cotton and fallow centre on extending application flexibility and residual activity of the herbicide on target weeds.
“S-metolachlor is registered for use in a wide range of crops, including sorghum, maize, sweetcorn, soybean, sunflower and cotton, as well as in fallow situations,” he says. “The new use patterns in sorghum, cotton and fallow centre on extending application flexibility and residual activity of the herbicide on target weeds.”
In sorghum, a rate of 1.0 to 2.0 L/ha can be applied either as a single application before the crop or weeds emerge, or as a split application pre and post crop emergence (up to 6-leaf stage). Similarly, the full rate can be applied after harvest to establish the fallow or 1.0 to 1.5 L/ha can be applied pre-emergent to weeds at fallow establishment followed by 0.5 to 1.0 L/ha within 4 weeks. Be sure to observe replant intervals when planning the next crop.
In cotton, a single application of 1 L/ha either pre-emergent (before, at, or immediately after, planting), over-the-top or directed stand-alone spray or over-the-top mixed with Roundup Ready herbicide on Roundup Ready FLEX® cotton.
“There are several factors that affect the length of effective residual activity of S-metolachlor, some of which are outside the grower’s control,” says Rob. “The product needs to be incorporated and has interactions with rainfall, temperature, soil type, soil organic matter and stubble. Having more flexibility in the application timing gives growers the ability to compensate for some of these factors and control new waves of weed germinations for longer.”
Untreated strips are a good indicator of the seed bank and potential weed burden in a field. The pre-emergent herbicide treated area on the left has far fewer weeds than the untreated section of the field on the right, which suffered significant yield loss due to feathertop Rhodes grass infestation.
S-metolachlor is only active on weeds that have not yet emerged and has no effect on weeds that have already emerged from the soil or that do not come in contact with the herbicide as they emerge from the soil. It is essential to control already-emerged weeds first and then apply the pre-emergent to control subsequent flushes of weed germinations.
“There are some situations where the residual herbicides will appear to be less effective than they should, but this can often be attributed to compromised application timing, limited rainfall and soil conditions, rather than herbicide performance,” says Rob. “The difficultly in achieving perfect application timing and incorporation with rainfall is one of the main reasons why the new use patterns for Dual Gold® have been registered. Pre-emergent herbicides are best used within the WeedSmart Big 6 integrated weed management program and not as a stand-alone control measure.”
While other crops listed on the S-metolachlor label can metabolise the herbicide, sorghum requires a seed safener to protect the germinating plants from the herbicidal effects of S-metolachlor. The new Epivio C® seed safener replaces Concept II® and provides better overall protection for sorghum seed.
S-metolachlor damage is seen as distorted and twisted growth in sorghum, the rightmost plant is unaffected (protected by seed safener).
In Syngenta’s product development trials in Queensland and NSW, they measured an 11 per cent increase in plant stand and a 7 per cent increase in sorghum yield in crops where the seed was treated with Epivio C®compared to Concept II®. Epivio C® has also demonstrated improvements in seed safety and shelf-life for carry-over seed.
“Epivio C® is applied as seed treatment and when the seed is planted into moist soil the product is taken up into the plant and improves the metabolism of the herbicide in the seedling, resulting in no crop symptoms,” says Rob. “The result is better crop establishment and healthier plants that can better compete against weeds that germinate later in the season.”
Epivio C plot trial demonstrating the benefit of the seed safener in supporting robust germination and establishment. No safener (left) compared to Epivio C safener (right).
There is evidence that growers can maintain crop yield and reduce summer grass seed production by planting sorghum crops at a density of 10 plants/m2 and a row spacing of 50 cm.
The WeedSmart Big 6 includes diversity in crops and pastures, crop competition and mixing and rotating herbicide mode of action groups.
More information

Podcast: Seed safener explainer (starts around the 22 min mark) 
Article: Weaponise sorghum crops to take out feathertop Rhodes grass and awnless barnyard grass

Ask an Expert

Can pulse cover crops tackle multi-resistant ryegrass in irrigated systems?

The best weed control comes from tactics that also bring other benefits to a farming system.
Greg Sefton, principal agronomist with Sefton Agronomics in the Riverina, says multi-resistant annual ryegrass is becoming a major problem in irrigated systems.
Greg Sefton, principal agronomist with Sefton Agronomics in the Riverina, says legume cover cropping is providing effective control of multi-resistant annual ryegrass in irrigated systems.
“Herbicide resistance can move easily through irrigation areas, particularly when the control methods used on the supply channels are limited to just a few herbicides,” he says. “The ryegrass here is generally accepted to have resistance to glyphosate (Group 9 [M]), Group 1 [A] such as clethodim, Group 2 [B] and Group 3 [D], such as trifluralin. Growers are now relying heavily on Group 15 [K] products such as Sakura, and doing their best to rotate out of the problem.”
To regain control, Greg is working with growers to incorporate a multi-purpose fallow crop such as field pea into the system as a winter fallow clean with the added benefit of contributing biological nitrogen into the soil ahead of planting rice or wheat. 
Earlier maturing varieties of field pea provide better weed control options than Kaspa field pea, chickpea and lupin, all of which generally mature later, sometimes after the target weeds have set seed.
“A competitive pulse crop terminated at maximum biomass is an excellent way to reduce weed seed set,” says Greg. “It is a cultural control that also enables the use of some herbicides that are rarely used in our system. Combining the herbicide and cultural methods in the WeedSmart Big 6 is an effective way to keep our cropping options open and to maximise the value of applied water.”

What is the best fit for the legume crop as a winter clean?
In brief: In the Riverina, the optimal place in the rotation is ahead of rice.
The details: Fields selected for rice production are usually bare fallowed for the preceding winter. The aim of the fallow is to control weeds and conserve soil moisture.
Some growers are having success with field pea sown in May as a winter cover crop then terminated for silage or as a brown manure in early September. This fits well with preventing seed set in annual ryegrass, including late germinating plants.
Field pea is a competitive legume and can suppress weed germination and growth when planted in the most competitive configuration possible with minimal soil disturbance and no gaps.
A knockdown treatment of glyphosate (Group 9 [M]), clopyralid (Group 4 [I]) and carfentrazone (Group G [14]) is applied at planting then a mix of pendimethalin (Group 3 [D]), clomazone (Group 13 [Q]) and paraquat (Group 22 [L]) is applied after an irrigation flush to initiate rice germination and prior to rice germination to knockdown both newly emerged barnyard grass (BYG) and persisting ryegrass. This provides a double knock on ryegrass whilst applying a pre-emergent herbicide for barnyard grass in the rice phase.
When implemented once every 4 or 5 years, with a diverse rotation of winter and summer crops in-between, growers can keep a lid on herbicide resistant annual ryegrass populations. 
Field pea is a competitive legume crop that can reduce annual ryegrass germination in the paddock and halt encroachment from the crop borders.
How do you manage weeds on the non-crop areas?
In brief: The same herbicide mix is applied to the whole paddock, including the weeds growing in the check banks.
The details: Weed seed, often carrying herbicide resistance genes, travels easily through irrigation systems and can colonise non-crop areas. Seed from these plants readily infests the cropping areas if not controlled effectively. The control measures used on non-crop zones are often limited to herbicide tactics, so it is important to make sure the herbicide is applied to maximum effect to prevent seed set.
Farm hygiene and physical removal of isolated weeds will also have a positive impact on weed seed production. 
What farming system benefits come with growing a legume cover crop?
In brief: A legume crop grown for biomass rather than grain can improved soil tilth and reduce crusting on some sodic soils. This practice also allows better soil nutrition management and keeps the grower’s options open if the water allocation situation changes.
The details: The field pea crop will fix atmospheric nitrogen and this allows the grower to use 100 to 150 kg/ha less urea to grow the following rice crop without any yield penalty. If there is insufficient irrigation water available for a rice crop, then the fixed nitrogen is still available for a winter crop of canola or wheat.
The phosphorus fertiliser required for rice can be applied when the field pea crop is planted, giving the phosphorus time to become more available in the soil and ready for uptake when the rice is planted.
Field pea is quite drought tolerant, so if irrigation water is not available for rice, the field pea can be grown through to harvest the grain and will usually yield 0.7 t/ha, which can be more profitable than, say, a 1 t/ha drought-affected wheat crop.
Building an integrated farming system based on methods that have multiple benefits is fundamental to staying ahead of weed pressure.
Practical tips for growing field peas as a brown manure crop
Pulses to attack weeds on many fronts


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163: Diverse rotations rock – good for profit, weeds and nitrogen!

CSIRO Chief Research Scientist for Farming Systems, Dr John Kirkegaard, joins us to tell us about current trial work he is leading looking at the impact of rotations on soil water, nitrogen, and profit in the face of variable climatic conditions.
Wimmera Farmer Tim Rethus joins us to update us on how he’s keeping his weed seed banks as low as possible. Tim was one of our farm hosts back in 2019 at Horsham WeedSmart Week. We’re going to find out what’s changed for Tim with his farming system and how he’s going to approach his summer weed control program.
And last, but not least, Tim Frazer, who farms in Chinchilla Queensland, has a chat with us about how he’s managing Group A (Group 1) and Group M (Group 24) resistance.
Webinar recording
 Our last webinar for the year was on Metolachlor usage in the northern region, presented by Rob Battalia from Syngenta, with WeedSmart Northern Extension Agronomist Paul McInstosh hosting. You can now watch it online here.
Case Studies
We have two new case studies for you to check out!
Jamie and Susie Grant, Jimbour Qld, over the years have adopted controlled traffic, minimum tillage, cover cropping and vigilant weed management as key strategies to maximise water infiltration and minimise losses to run-off, evaporation and wasted evapotranspiration throughout the year. Learn all about their farming system in this case study here.
Peter and Kylie Bach from Pittsworth Qld are aiming for 130% utilisation of their cropping land through the year. Peter and Kylie Bach have developed a farming system that extracts full value from barley stubble and minimises weed pressure. Learn all about their farming system here.


162: Regional Update – Bernie Quade, Agronomist, Wyalkatchem, WA

Bernie talks to us about how frost has affected his region and provides some tips on Summer weed control.
This is our last Western Region Update for the year! Thanks to Bernie for coming on and having a chat with us!  Give Bernie a follow on Twitter here.


161: Getting residual herbicides right after harvest

We hear from ICAN’s Mark Congreve on this (pictured above).
Northern Grower Alliance CEO Richard Daniel also joins us to talk about summer weed control and how using an optical spray can maximise your use of residual herbicides.
We also hear from Frankland based Agronomist, Tim Trezise, who had a query on the challenges around crop topping weeds at the dough stage and whether you still get good control by using higher rates of paraquat or glyphosate. Pete answers this question in the podcast!

Podcast: Why crop topping is a great tool to prevent weed seed set
Podcast: Richard Daniel explains results from Northern Grower Alliance survey on optical spraying
GRDC: Consider plant back implications after herbicide use
Webinar: Register for our webinar “Metolachlor usage in the northern region” 

Case Studies

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Case Study

Jamie and Susie Grant, Jimbour Qld

Jamie and Susie Grant are always on the front foot when it comes to storing soil moisture to maximise yield in their dryland cotton crops on ‘Kielli’ near Jimbour on Queensland’s Darling Downs.
Over the years they have adopted controlled traffic, minimum tillage, cover cropping and vigilant weed management as key strategies to maximise water infiltration and minimise losses to run-off, evaporation and wasted evapotranspiration throughout the year.
The Grants have implemented an integrated weed management system that incorporates several of the WeedSmart Big 6 strategies, with an emphasis on preventing weed seed set.
Cover cropping provides crop competition
Jamie says they have not grown a winter crop for over 20 years and have phased out other summer crops, such as sorghum, in preference for dryland cotton.
“For the last 15 years we have grown French millet as a summer cover crop on half the cropped area. And this year we are moving to a new configuration where we will have the whole farm sown to millet and cotton in alternate bays,” says Jamie.
Cotton sown into French millet cover crop stubble.
The plan is to plant cotton on 3 m row spacing across the whole cropped area (instead of on rows 1.5 m apart on half the farm). Between the cotton rows will be a 1.5 m swath of millet on 380 mm rows, leaving 750 mm between the edge of the millet and the adjacent cotton row. The following year the cotton rows will be planted through the centre of the millet swath.
Jamie expects this system to increase infiltration and storage of moisture across the farm and to support a higher yielding cotton crop.
“During summer, the soil will be better protected from erosion with ground cover spread over the whole farm, and in a good rainfall season the soil reserves should be refilled and available for use in a subsequent drier year,” he says. “We have done a small, 9 m wide trial of the new configuration and the difference in cotton yield was phenomenal.”
Summer weed management begins with a double knock prior to planting both millet and cotton to ensure the crops can establish in a weed-free environment. Millet is planted in October then sprayed out when the stalks have reached maximum cellulose level but before the plants set seed. The cellulose-rich stalks reach about a metre in height within about six weeks of planting.
When the crop is sprayed out, the stalks collapse to produce a 100 per cent mulch cover that protects the soil surface from evaporation and erosion, while allowing rapid infiltration of rainfall and suppressing weed germination, especially over summer. Volunteer cotton is controlled if necessary in the millet.
The Grants follow industry best practice for the in-crop management of weeds in their Round-Up Ready cotton.
Preventing weed seed set in winter fallow and in-crop
Over 15 years ago Jamie and Susie invested in optical spray technology to better manage their fallow weeds, but it was never the full solution. The problem of treating weeds of varying size and maturity meant that weeds were an ongoing drain on their precious soil moisture stores.
“When we bought one of the first WeedSeekers into Australia we knew we would reduce our herbicide use in the fallow, but the time taken to treat weeds using the optical weed detection technology was a limiting factor,”says Jamie. “Before long we had moved to a wider WeedSeeker boom just to get across the country quick enough. Then we added a broadacre spray behind the WeedSeeker to pick up the smaller weeds – the whole system just wasn’t working well enough due to labour and timeliness factors.”
When Jamie heard about the development of the SwarmFarm robots he was keen to be part of the early testing phase and was the first grower to deploy a SwarmBot – named November – under commercial conditions.
“I knew from the start that the robotic platform would solve our weed control problems and could see the potential for this technology to revolutionise the way we farm,” he says. “We have since leased a second robot – Victor – practically eliminating the need for a broadacre sprayer. The next modification will be to give the robots higher clearance so we can conduct in-crop weed control right up to canopy closure in the cotton.”
Robotic spot spraying in cotton inter-rows.
Jamie and Susie were controlled traffic pioneers, so the move to lightweight machines for all their field operations, other than harvesting, is the ultimate aim. Jamie expects the robots to be able to undertake all the spraying, ground preparation, planting and fertilising operations and wheeltrack renovation within the next few years. This relies on the fine-tuning of the SwarmBot auto-refilling capability.
The current use of the two robots, each fitted with a 9 m WEED-IT boom and 1000 L tank, for fallow weed spraying has halved the Grant’s herbicide use compared to the 27 m wide WeedSeeker boom.
“The difference in herbicide use has come through more proactive use of the optical weed detection technology, rather than reacting once we saw weeds growing in the field,” says Jamie. “We are continuously spraying and treating smaller and smaller weeds, with very, very few misses. We are always on the front foot with weeds now, so we can take advantage of any planting opportunities that arise, without having to wait to spray weeds ahead of the planter.”
The robots also earned their place on the farm during the drought by preventing the establishment of weedy patches. Jamie can justify the use of different chemical groups in fallows that might otherwise be considered too expensive, and herbicide resistance has all but disappeared.
The robots have prevented the establishment of weedy patches and allowed the use of a wider range of herbicide groups in the fallow.
The robots work at a slow, steady pace, providing a more stable platform for the boom than the much wider WeedSeeker rig, and enabling the sensors to detect very small weeds – down to just 5 mm in diameter. The operation is repeated every two weeks, so weeds never have the opportunity to mature or set seed.
The WeedSeeker typically sprayed between 5 and 7 per cent of the paddock area compared to the WEED-IT on the robots spraying just 2 to 3 per cent of the paddock due to the small size of weeds and the accurate spray pattern.
The glyphosate is very effective on small weeds and any misses or hard to kill weeds are captured with an application of Starane (Group 4 [I]) or Biffo (Group 10 [N]) – using hardly any product doing an excellent job on the few remaining weeds. After planting cotton Jamie applies paraquat to be on the safe side when it comes to minimising the risk of glyphosate resistance.
 “After planting we expected to park the robots until the cotton crop was finished, but in fact we are finding more and more jobs for them to do,” says Jamie. “We are already using them to apply foliar fertiliser and early in-crop weed control. We are working toward eliminating the need for the high clearance Spra-Coupe for in-crop spraying.”
Using the robots, the Grants have reduced the amount of herbicide used in-crop by at least 50 per cent, and most likely close to 70 per cent, by only spraying the inter-row area and not the cotton plants. Achieving this has been as simple as blanking off three nozzles over each cotton row.
“Although the sensors on the WEED-IT respond to some of the cotton leaves in the inter-row, there is still a large reduction in the amount of herbicide used compared to the blanket spray using the Coupe,” says Jamie.
After rain, 28 per cent weed cover is the highest weed density that the Grants have sprayed using the robots. At this density they would have previously chosen to use the broadacre sprayer rather than the WeedSeeker boom. Jamie says the robots had no problem taking care of the situation, but they did require several refills. He hopes to get to the point where the robots only require checking and filling once a day, and he is ‘in on the ground floor’ assisting SwarmFarm with the auto-refilling trials.
Jamie says automatic refilling of the robots will be the next big step up for spraying efficiency.
Ultimately, Jamie would like to have enough robots to keep one staff member occupied full time. Even now, having Victor and November taking care of the farm’s weed control program allows skilled farm staff to spend their time doing more interesting work with their trade or other skills, rather than the boring job of operating a spray rig in fallow.
Along with the many other benefits, Jamie considers Victor and November to be the safest spray ‘operators’ in the business because they start and stop spraying in response to the weather conditions as detected by the on-board weather station.
“The robots will not deviate from the set weather parameters,” he says. “A weather app is being developed and will soon be available to monitor and record the whole spray operation and weather conditions at the time of spraying.”

Case Study

Peter and Kylie Bach, Pittsworth Qld

Their 1000 ha farming operation, Kurilda Ag, is based near Pittsworth on the Darling Downs in Queensland, an area known for its reliable rainfall and deep self-mulching black clay soils. Peter says the recent long string of dry years has clearly demonstrated the value of stubble cover in their zero till, controlled traffic system.

“We are using crops to compete with weeds for as much of the year as possible,” he says. “We double crop whenever there is sufficient soil moisture to plant and having only short fallow periods most years reduces the opportunity for weeds to take hold.”
Peter and Kylie have been farming for 15 years, with a focus on summer crops, mainly sorghum and mungbean. Barley is grown in winter, predominantly for stubble cover to conserve moisture.
About five years ago they bought a Shelbourne stripper header and an Emar chaff deck for their harvester to achieve the dual purpose of conserving standing stubble and implementing harvest weed seed control. Their weed management program includes most of the WeedSmart Big 6 tactics that minimise the impact of weeds on their business.
Shellbourne stripper front is used in barley to conserve more standing stubble.
“Our main aim at the time was to deal with a large population of Johnson grass on a farm we had recently bought,”says Peter. “Although it is relatively easy to control Johnson grass with herbicide, we wanted to try a non-herbicide method to reduce the weed seed bank as quickly as possible.”
Across the farm, Johnson grass is now under control and feathertop Rhodes (FTR) grass, sowthistle and fleabane are the main problem weeds.
“Generally, when we keep on top of feathertop Rhodes that also manages the fleabane,” says Peter. “Sowthistle is getting harder to kill and we suspect glyphosate resistance is increasing. We also know of a few small areas of resistant ryegrass.”
The transition from barley to mungbeans, or barley to sorghum, provides the opportunity to use a different suite of chemicals. The Baches generally stay away from Roundup Ready (RR) crops and are using more soil residual herbicide in their program than they did previously.
Peter says there are more options available now, particularly with soil residual chemistry, to enable increased chemical diversity with the crops they grow.
“The residuals are chosen specifically with the next crop in mind,” he says. “With inconsistent rainfall patterns it can increase the risk of crop injury if there is insufficient rainfall to break down the chemical before the next planting.”
Metolachlor (Group 15 [K]), such as Dual Gold, plus glyphosate (Group 9 [M]) is applied at the end of July or early August in preparation for grain sorghum. After the sorghum crop is harvested, Peter prepares to plant barley. After the barley crop he then applies a residual herbicide like imazethapyr (Group 2 [B]), such as Spinnaker, ahead of mungbean crop emergence.
They have an optical boom sprayer but are finding it gets less use these days with less area being fallow managed.
Peter says that crop competition through frequent cropping maintains pressure on weed numbers, but to sustain this intensive cropping program they need to maximise the soil moisture levels throughout the year with ground cover and standing stubble.
Peter Bach says the ability to keep growing crops throughout the year keeps the pressure on weeds.
“Retaining stubble has been our standard practice for years but the lack of stubble produced by mungbeans was a weak link in the system,” he says. “We were interested in the stripper front for use in barley, and a grower in the Riverina gave us the confidence to give it a go.”
The mungbean crop benefits from the tall barley stubble and responds with higher yield. After the mungbean crop is harvested, the barley stubble tends to lay over, giving excellent ground cover that also benefits the following crop. The stripper front essentially maximises the benefit of the barley crop for the whole rotation, and has counteracted the effect of drier seasons.
“Soon after we bought the stripper front and chaff deck the rain stopped and a long series of dry years set in,” says Peter. “The tall stubble from that first barley harvest made it possible for us to keep growing crops for at least two years on very minimal rainfall. Since then it has helped make the most of every rainfall event and is a key part of our farming system.”
The standing barley stubble benefits the following mungbean crop and continues to provide good ground cover after the mungbeans are harvested.
They currently use XL spearpoints on CR600 units on their tyne planter, which does an excellent job planting barley on 38 cm (15 inch) row spacing, but the Baches plan to reduce the row spacing in barley to 25 cm (10 inch) and will most likely change from the tynes to a disc system.
An NDF disc opener planter is used for summer crops, which are planted on 76 cm (30 inch) rows. All crops are sown using moisture seeking techniques, which Peter says is more important than precision planting when it comes to achieving even crop establishment.
“Although we have had a few failures with deep planting, it has generally been a good strategy for us,” he says. “The key is to plant deep but not put too much soil back over the seed. In drier years we also reduce the seeding rate to ensure even germination. Early summer planting dates seem to be the best-bet option for our district.”
The aim is to plant mungbeans between the rows of fresh barley stubble that is standing up well, but if the planter gets off line it can be hard to achieve proper seed-to-soil contact with the high level of stubble present. Ultimately, it would be good to have GPS steering on planter bar to ensure the planter tracks exactly between the rows of stubble.
In the lead-up to harvest both mungbean and sorghum crops are desiccated but this operation is too late to stop seed set on late germinated weeds. To prevent weed seed set in these in-crop escapes Peter is working on system that can be used to spray weeds in the inter-row just before the sorghum starts to flower.
At harvest the Emar chaff deck is used in all crops, every year. In the last five years this harvest weed seed control tool has had a massive impact by reining in large populations of Johnston grass.
“The chaff deck applied consistent downward pressure on the Johnson grass seed bank every year and also helps us manage feathertop Rhodes grass,” says Peter. “Of course, the benefit is most noticeable when populations start high, but it is also good to know that it is also effective in keeping numbers low across the farm.”
He has also noticed that the chaff deck is very effective in controlling volunteer crop plants. Having all the weed seed and any grain that was thrown out the back of the harvester placed on the wheeltracks makes control much easier and more effective.
“When we do fallow sprays, we run larger nozzles over the wheeltracks to make sure any weeds that germinate are controlled before they can set seed,” he says. “In some instances, the only weeds present in-crop are along the wheeltracks so we can just turn on the six nozzles running over the three sets of wheeltracks.”
The combination of the stripper front and the chaff deck has resulted in more crop and less weeds at ‘Kurilda’, even through a series of very dry years.

Case Study

Elton and Pam Petersen, Moonie Qld

A SwarmFarm robot, ‘Oscar’, has added another dimension to Elton and Pam Petersen’s integrated weed management program, which features the majority of the WeedSmart Big 6 tactics.
In two summer fallows the Petersens have regained control of glyphosate resistant feathertop Rhodes grass (FTR) and awnless barnyard grass (BYG) that was threatening their 2000 ha dryland cropping operation at Moonie, on the Western Downs.
Elton and Pam Petersen, ‘Traighli’ near Moonie on the western Darling Downs.
The Petersens have achieved this remarkable feat after deploying ‘Oscar’ with a 12 m weedIT boom attachment. In the 20 months that Oscar has been spraying weeds in the summer fallow, ‘he’ has clocked up over 3000 hrs and passed over more than 25,000 ha.
Elton and Pam purchased ‘Traighli’, a 2370 ha grain and cattle property 5 km north of Moonie, on the western Darling Downs, in 2015. Previously they had farmed on the Fraser Coast growing sugarcane, soybeans and pineapples, and running cattle.
At the time of purchase, weeds that adapt well to conservation cropping systems had established populations that were impacting on the profitability of grain production. Elton’s initial plan was to use cultivation and blanket spraying to regain the upper hand, particularly of the herbicide resistant summer-growing grass weeds.
“Cultivation certainly helped reduce weed numbers, but was never intended to be a long-term, sustainable solution to manage these weeds. It was also too costly to use the blanket sprayer frequently enough to prevent seed set,” said Elton. “We were interested in optical spot spraying technology and everyone we spoke to who used this technology gave very positive feedback – except that it was still not practical to spray as frequently as is required to target small weeds.”
After further investigation the Petersens decided to invest in technology that would maximise the efficacy of the optical spot sprayer in their weed control program.
“Our choice was between a 36 m tow-behind weedIT boom and a 12 m weedIT boom mounted on a SwarmFarm robot,” said Elton. “We saw the robotic platform as a way for us to really hit our grass weed problem hard and to drive down the weed seed back as quickly as possible, with minimal operator input.”
The Petersens with SwarmFarm founders Andrew and Jocie Bate and SwarmFarm team members Tom Holcombe and Jarrod Jackson.
“In such a short space of time we have dramatically reduced the seed bank to the point where Oscar can work for up to 40 hours scouting and spraying weeds without the spray tank needing to be refilled,” said Elton. “This fact alone is incredibly important. It gives us much more freedom without compromising the weed management program.”
Elton has also experienced a significant mind-set change to weed management as a result of deploying Oscar. Applying constant pressure to small, fresh weed seedlings has seen the weed seed bank dwindle as no new seed has been produced for two summers.
When blanket spraying, Elton knew he was compromising on water and chemical rates in the interests of saving money and time. He said the focus was always on trying to make the spray operation more efficient and this often resulted in some weeds being larger than ideal when the herbicide was applied.
“With a tow-behind optical boom we would have improved our chemical and water application rates but not solved the frequency and consistency problem we had with the blanket spray system,” he said. “Automation brings the consistency. If Oscar goes out spraying and finds only a few weeds it only costs us $0.50/ha in diesel, and we are paying for the machine whether we use it or not.”
In the 2020/21 summer fallow, chemical costs totalled just $12.80 per ha for all the summer weed control and the pre-plant knockdown spray. Elton says this is equivalent to the cost of a single blanket spray in the past.
“In our old system we were never on top of resistant weeds and although the new system probably has similar costs, we are achieving a much better result,” said Elton. “We have essentially invested in technology that does a better job with less chemical – the long-term benefits have been realised more quickly than we dared to hope. The saving in chemical cost is even greater than I expected.”
Summer fallow spray program
In the 2020-21 summer fallow Oscar completed seven passes of the whole farm between mid-November 2020 and May 2021. For the 25-week fallow period, the property received around 650 mm of rainfall (more than the annual average for the property), with the longest stretch without rain being just 10 days. Being able to send Oscar out spraying almost immediately after rain has allowed the Petersens to treat each new germination of weeds while still very small. Elton also has Oscar set to only spray when the conditions are cool, to maximise herbicide uptake.
BYG sets seed very quickly, even quicker than FTR, so there is no opportunity to stop seed set other than killing the seedling before it seeds. Elton believes he is on track to eradicate both of these grass weeds within the next few years and will be able to reduce or eliminate the use of Group A herbicide in the summer fallow.
He says they are currently applying Group A herbicide in three passes, but each round is only using one drum of Group A product, across the 2000 ha cropped area.
The other fallow sprays are glyphosate immediately after harvest and after the first rain (for crop volunteers) and then the pre-seeding knockdown.
“This property is heavy grey cracking clay soil and melon hole country, so we have really noticed a difference in being able to access the paddocks with such a light machine much sooner after rain than is possible with a tractor,” said Elton. “Everything is centred on hitting weeds when they are very small and at their most susceptible to herbicide. This has resulted in a large reduction in the amount of chemical used.”
Another feature that Elton uses to enhance the efficacy of the pre-plant herbicide treatment is to slow Oscar down and increase the sensitivity of the optical detection to ensure that the very smallest of weeds are ‘seen’ and sprayed. This essentially saves them the cost of a pre-plant blanket knockdown.
Very clean fallow in the background compared to two passes that were missed due to an error in the robot’s instructions.
Winter weed control tactics
The Petersen’s winter cropping program is limited to growing chickpea, wheat and barley, so although they rotate the available chemistry, their options are restricted. When the opportunity arises they plant a summer crop followed by a winter fallow to target black oats and phalaris.
“We do one in-crop spray in wheat to target these grass weeds and are aware of the risk of Group A resistance in black oats, and a second in-crop spray is to control broadleaf winter weeds,” says Elton. “We use robust rates and ensure there are no survivors. A targeted winter fallow program would also go a long way to reducing the impact of herbicide resistance in black oats.”
Chickpea crops are now sown on the same 375 mm (15 inch) row spacing as the cereals, which is proving beneficial in both higher yield and weed suppression compared to the 760 mm (30 inch) spacing used previously in chickpea. Pre-emergent herbicide is applied ahead of chickpeas and in summer crops.
“We set our planting date to avoid frost risk and want to get the crop in as quickly as possible and have the option to use moisture seeking techniques in dry years,” says Elton. “You can’t overestimate the effect of canopy closure on weeds and evaporation.”

SwarmFarm: Targeting small weeds all year

Case Study

Single family, Coonamble NSW

Tony and Sharon Single farm with Tony’s parents John and Mary, south east of Coonamble in northern NSW with views of the Warrumbungle Range.
Across the 4500 ha cropping area at ‘Narratigah’, the weed numbers are low as a result of the Single’s ‘farming moisture’ philosophy, which involves planting whenever there is sufficient subsoil moisture to establish a competitive crop on their heavy clay soils. Their location allows a mix of summer and winter cropping, so if there is an opportunity for a summer crop they take it, even if that might result in missing the winter crop.
Tony (left) and John Single use their Single Shot weed detecting drone to scout for and map weeds to create a prescription map for their tractor mounted boomspray.
“Farming moisture is our risk management strategy and it has paid off time and time again,” says Tony. “We are really farming with probability and by reducing our risk we have been able to maximise profits. If there is insufficient subsoil moisture we just don’t plant. This means we have very few failed crops and we take advantage of the intermittent winter fallows to run down the seedbank, particularly for winter-active grass weeds.”
Tony says the area has a slightly summer dominant rainfall pattern but rainfall is very variable. The main crops grown are wheat, chickpea and sorghum, along with any other crop that might fit a certain planting opportunity.
While their cropping decisions are very water responsive, there can be situations where the need for ground cover outweighs other considerations. This can occur after a chickpea crop and if they feel it is necessary, Tony and John will plant a crop just to produce stubble, knowing that the yield will most likely be low.
“Generally, if it is too dry to plant we will choose to fallow to build up the soil moisture profile knowing that this is the least-risk strategy and gives the best result in the long term,” says Tony. “We can effectively gain good weed control for the full 12 months through the use of cropping and fallowing in both winter and summer.”

Resistance status
Herbicide resistance is considered the biggest threat to their business even though they currently have resistant weeds well under control. Glyphosate resistance was first confirmed at ‘Narratigah’ in 2005 in annual ryegrass, and Tony and John are also aware of some small areas of glyphosate resistant barnyard grass.
“These are our most important weeds and keeping a lid on resistance is crucial to prevent them becoming limiting factors in our cropping choices,” says Tony. “We also have other weeds including milk thistle, fleabane, blow-away grass and feathertop Rhodes grass – the full suite of northern region weeds really.”
Tony says their efforts to consistently drive down the weed seed bank, and having regular winter fallows, minimises the impact of herbicide resistance on their business.
“Our weed seed bank is low and weeds do not dictate our cropping decisions,” he says. “Ryegrass has a relatively long growing season so we have ample opportunity to stop seed set through a winter fallow. There are also several chemical options for use with our spot spraying technology and new pre-emergent herbicide options too, along with cultural controls such as chipping.”
“We are more concerned about the implications of resistant barnyard grass, which washed in from up-stream. Barnyard grass has the ability to germinate and very quickly set seed, making it more difficult to contain.”
To avert the risk of more seed being deposited by overland flow, the Singles have constructed a number of diversion banks on the up-stream side of their cropping area to divert water.
Tony is also noticing ‘rate creep’ as weeds like milk thistle that are slow to metabolise herbicide, become harder to control. He says they are needing to use a higher rate of paraquat in the double-knock applications. The Singles are managing this through regular double-knocking in fallow and strategically using saflufenacil with paraquat to enhance control.
Black oats currently has a low resistance profile due to the use of winter fallows and fop chemistry is still effective in many paddocks.
The Singles use their proprietary drone weed mapping system ‘Single Shot’ to scout for and map weeds, helping them to better plan for and implement each herbicide application.
Their integrated weed management system is an excellent example of the WeedSmart Big 6 in practice.
#1 – Diversity in cropping
The combination of winter cereals, winter pulses and summer cereals provides many opportunities for controlling weeds pre-season and in-crop.
“The decision to plant sorghum is driven by weed and disease pressure in winter crops,” says Tony. “In a paddock that is becoming difficult to manage, we would rather change to sorghum than turn to a heavy reliance on pre-emergent herbicides and in-crop spraying of winter weeds in winter crops. Swapping to a summer crop gives us the opportunity to target problematic weeds using a winter fallow phase.”
This practice, plus the persistent drought in recent years, has resulted in more fallow area and allowed them to drive down the weed seed bank of annual ryegrass and black oats. It is now very rare for them to target grass weeds in-crop in winter cereals.
Using their drone and sensor to scout for and map weeds in the fallow periods has been a powerful tool to attack the weed seed bank in both summer and winter. Decoupling the weed detection and spraying operations opens up opportunities for more diverse weed control.
Tony and John can use the drone to map the presence of weeds just before, or soon after, significant rainfall events. Once they are able to get on the paddocks with the sprayer they can target previously existing weeds with spot spraying an effective herbicide mixture while applying a blanket rate to the new germination of weeds following the rain.
Knowing exactly what is in the paddock before they start spraying means they can consider a wider range of potential chemical options or techniques. Once the plan is made, they know how much product they will need and the cost. Knowing that they will only be treating say 5 ha in a paddock, they can afford to use chemicals that they would never consider for a blanket spray application.
#2 – Mixing and rotating MOA
Tony and John use some preemergent chemistry strategically in fallows to maximise weed control diversity while keeping their options open for cropping.
They aim to use a preemergent application to control key broadleaf and grass weeds after harvest, which takes the pressure off glyphosate without compromising planting opportunities the following autumn.
A combination of soil residual herbicides such as picloram, Balance and Flame has given good results early in the summer fallow, followed with a pre-sowing double knock of glyphosate and paraquat, giving a total of five chemical groups targeting fallow weeds. When it suits the program, they use chemistry mixes such as Sharpen + paraquat in the double knock, increasing the modes of action and increasing the efficacy of the treatment on the weed spectrum.
In addition to the use of preemergent chemistry, winter grass weeds are also targeted in broadleaf crops, usually with clethodim (Group A, Group 1), but the Singles are aware of the resistance risk and are looking to introduce Clearfield canola as alternative means of grass control in break crops, and to bring more diversity to their system.
Using their drone mapping technology, Tony and John can merge multiple flights of a paddock during the year into one map to show the location of all the weeds detected. This map can then be used to apply a site-specific soil residual herbicide for the next season to say 15 to 20 per cent of the paddock. In treating smaller areas, they can afford to consider chemistry that might otherwise be too expensive, add more diversity to chemicals used and reduce their plant-back risks.
#3 – Crop competition
The Singles consider crop competition to be their #1 weed control tactic, simply because it is the only one that provides season-long in-crop weed control.
“We do everything we can to maximise the crop’s ability to suppress weeds,” says Tony. “This starts at planting, where we have invested in planting gear with moisture seeking capability so we can plant crops on time and ensure good establishment. We take great care to ensure there are no gaps for weeds to exploit, and always square-off the headlands.”
Planting at 330 mm row spacing allows for inter-row sowing and stubble retention, and planting rates are chosen to maximise yield – with long-season wheat sown at 40 to 60 plants/m2, and later plant wheat sown at 80 to 100 plants/m2. The slope of each paddock dictates the tramline direction to be perpendicular to the overland flow, which results in most paddocks being sown north south.
For all crops Tony aims to achieve 100% knockdown prior to planting with a double knock treatment, followed with a well-established, vigorous crop.

#4 – Double knock
The Singles started using the double knock tactic twenty years ago in their winter fallows, and introduced it to summer fallows about ten years ago.
“The double-knock strategy hasn’t added significantly to our overall weed control costs,” he says. “When we first started using the double-knock we counted it as a direct cost to the system, but we now see the second knock with paraquat as a preemptive strike on future weeds – an investment in lowering the weed seed bank, and we are picking up savings with lower volumes of chemical required in subsequent weed control applications.”
The double knock tactic is now embedded in their weed management strategy and they have invested in spray gear to allow them to cover their area within the recommended 7 to 8 day window. Tony says the high level of control they achieve with the double knock means there are fewer and fewer weeds each year and this reduces the cost of the operation, particularly now they have the capacity to spot spray weeds with highly consistent weed detection.
“This tactic puts a significant dent in the weed seed bank and reduces the number of large and potentially stressed plants being sprayed,” says Tony. “This makes it a very effective resistance tool, particularly for our hard to kill weeds.”
#5 – Stopping seed set
The Singles are aiming for 100 per cent weed control in fallow, particularly for annual ryegrass and BYG, by managing paddocks in a site specific way at a square metre level using their drone scouting technology.
“The drone can effectively scout for weeds at a rate of 200 ha/hr, which makes it very quick and easy to scout a paddock and then go out and chip the five or so plants that might be left growing in a paddock,” says Tony. “This moves us closer to achieving 100 percent weed control. We have really driven down our weed numbers and significantly reduced the impact of herbicide resistance in our operation.”
Occasionally, Tony will drive along the tramlines in the side-by-side and chip out any grass weeds in chickpeas that have either escaped control or germinated late in-crop. Then prior to harvest, Tony and John look for any patches of weeds that have escaped control and take action to prevent seed set.
“If we find there is a patch of weeds getting away from us we don’t hesitate to sacrifice small areas of the crop to prevent seed set,” says Tony. “In 2020 we had a three or four hectare patch of ryegrass and decided to use a small slasher to mow the crop and weeds then sprayed the area with paraquat. That way we made sure the weeds did not set seed and prevented the spread of resistant weed seed at harvest.”
The Singles do not spray any selective herbicides outside their cropped area and prior to harvest they slash a 2 m width of crop along fencelines to stop the header bringing weeds into the paddock from the fenceline.
#6 – Harvest weed seed control
Several years ago, the Singles trialed narrow windrow burning for harvest weed seed control but decided that the negative effects outweighed the weed control benefits.
“For us, ground cover is supremely important for erosion control, reducing evaporation and increasing infiltration through the heavy clay soils,” says Tony. “We are watching the developments in impact mill technology and will most likely go down that path if we feel harvest weed seed control is needed in the future.”


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S-Metolachlor usage in the northern region

In this WeedSmart webinar, we talk to WeedSmart northern extension agronomist Paul McIntosh and Syngenta’s Field Biology Manager Rob Battaglia about how S-Metolachlor (Dual Gold) works, its efficacy, and what potential resistance problems might be around the corner. They explain what tactics growers should adopt to reduce potential resistance problems on this key grass weed herbicide, referring to the WeedSmart Big 6.
Topics covered include:

Application considerations for maximum efficacy
Effect of stubble
Herbicide solubility
Herbicide binding characteristics
Herbicide safener “EPIVIO-C”


Detect, then spray

For the past few years John Single and his son Tony have been using the air-borne weed sensor, Single Shot, developed by John’s other son Ben, to rapidly detect and map weeds on their dryland cropping property, Narratigah, near Coonamble, NSW. Read more here.


Optical spray has a good fit in CQ

CQ grain grower Kurt Mayne bought a weedIT boom in 2019 and has been impressed with the benefits that have come with the addition of an optical sprayer to their weed control program. Find out more here.

Fact Sheets

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Fact Sheet

Changes to herbicide Mode of Action (MoA) names

The global MoA classification system is based on numerical codes which provides infinite capacity to accommodate new herbicide MoA coming to market, unlike the alphabetical codes currently used in Australia.
Farming is becoming increasingly global. Farmers, agronomists and academics around the world are now, more than ever, sharing and accessing information to assist them to grow crops, while managing sustainability issues such as herbicide resistant weeds. It’s important then that the herbicide MoA classification system utilised in Australia be aligned with the global classification system. This will ensure more efficient farming systems into the future and allow Australian farmers and advisors to access the most up-to-date information relating to managing herbicide resistance.
CropLife Australia is working with key herbicide resistance management experts, advisors and the APVMA to ensure farmers and agronomists are aware of the planned changes.
The numerical classification system should be fully implemented by the end of 2024.
You can find further information by reading the factsheet and visiting the CropLife website here.

Fact Sheet

Sustainable glyphosate use in winter grain cropping systems in southern Australia

The number of glyphosate resistant weed species present in winter grain crops, along fencelines and in irrigation channels in Australia.

You can reduce the risk of glyphosate resistance in weeds if you follow the recommended practices in this factsheet.

Fact Sheet

Sustainable glyphosate use in Australian vegetable production

The number of glyphosate resistant weed species present in Australian vegetable production systems is increasing.

You can reduce the risk of glyphosate resistance in weeds if you follow the recommended practices in this factsheet.

Fact Sheet

Sustainable glyphosate use on roadsides, railways, public utilities and parks

The number of glyphosate resistant weed species present on Australian roadsides and railway lines is increasing.

You can reduce the risk of glyphosate resistance in weeds if you follow the recommended practices in this factsheet.

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