16th July 2021

Statement on volatility of Overwatch® Herbicide.

There have been suggestions that Overwatch® Herbicide is made volatile by moisture and causing off-target damage in nearby paddocks.

The potential volatilization of bixlozone applied to soil has been tested by FMC under both field conditions and controlled conditions in a wind tunnel, including conditions that could be considered as worst-case scenario. These investigations demonstrated that the amount of volatilization was very low, even when the product was not incorporated into the soil. Also, bixlozone, the active ingredient, is expected to degrade rapidly in air, with a half-life of around 6 hours.

This data indicates that volatility is unlikely to be a significant source of off-target movement of bixlozone. The APVMA assessment also concluded that Overwatch Herbicide is not considered to be a volatile herbicide.

The extent of off-target bleaching observed in reports our team have investigated, has occurred tens or hundreds of metres from the site of application. Available data and information demonstrate that this off-target movement of Overwatch Herbicide is attributable to drift. This is also evident from a wide variety of experiences across all major broadacre cropping zones in Australia where Overwatch® Herbicide has been applied successfully without off-target bleaching.

Most importantly, we continue to work closely on a case by case basis with growers and our retail agents. Please reach out to your retail agronomist or contact us on 1 800 901 939 if you have any issues, questions, or positive feedback to share.

A new herbicide, offering excellent Annual ryegrass control with a host of other weeds, is now available as a pre-emergent option in Wheat, Barley and Canola.

Overwatch® Herbicide, from Agricultural Sciences company FMC, has been showcased in trials for several years and will have its first year of commercial sales in 2021.

FMC Southern Regional Sales Manager, Simonne Read, said sites around the country included a major demonstration at Roseworthy, north of Adelaide.

“Roseworthy was predominantly an Annual ryegrass site, we had some good Ryegrass pressure and there was also some Bifora and other Broadleaf weeds,” Ms Read said.

"Overwatch® Herbicide is a unique herbicide, it’s a Group Q and offers a new option for growers to use as a pre-emergent. Registered to control Annual ryegrass but also picking up several broadleaf weeds - particularly Bifora - and Brome grass, Barley grass and Silver grass, Overwatch Herbicide ® also offers suppression of Radish and Capeweed, so the spectrum's quite nice.”

The site featured Overwatch® Herbicide demonstrations on each of the three registered crops, Wheat, Barley and Canola, as well as tank mixes with other herbicides. “Where we tank mixed it, particularly in a Canola TT situation, when tank mixed with a product such as Atrazine, or Simazine, we are really seeing an increase in the robustness of the chemistry,” Ms Read said.

“From a grower's perspective, we're taking a break from the traditional chemistry that's been used in that space and allowing the grower to bring in a new mode of action to combat that number one weed, Ryegrass.”

She said Overwatch® Herbicide gave comparable levels of control to the leading Annual ryegrass products on the market and the additional weed spectrum and alternative mode of action made it an excellent choice for growers.
“Like any pre-emergent herbicide, there's no silver bullet. It's a management program that needs to be taken into consideration but as a standalone herbicide, it is certainly offering a very satisfying level of control.”

Overwatch® Herbicide is also compatible with a broad range of other pre-emergent herbicides to broaden weed spectrum or to provide higher levels of weed control. Incorporating other modes of action is also recommended as part of an Integrated Weed Management (IWM) strategy to delay the onset of herbicide resistance.

The three crops on the label also provide growers with greater flexibility to consider the weed spectrum and the chemistry that has been used in the past.

“If Overwatch® Herbicide suits that spectrum of weeds in that paddock, they've got flexibility to be able to come in and make a cropping decision at the last minute. Growers could be planning on planting Canola and if the season has a dry start and goes beyond that optimum window of sowing Canola, they can easily alternate to Wheat or Barley.”

“Overwatch® Herbicide really does open up the spectrum of options that the grower can have when combatting a weed spectrum within their paddock.”

The herbicide is applied at 1.25 L/ha and should be incorporated by sowing. It has some unique and visual characteristics in controlling the weed species.

“With this product the Ryegrass actually emerges, and with the chemistry working on the plant, it runs out of energy and it turns this unique, pink colour,” Ms Read said.

“Overwatch® Herbicide shows good residual control for up to 12 weeks so later in the season we were still seeing the product being taken up by late emerging Ryegrass plants.”

She said Overwatch® Herbicide has been extremely consistent across many years and different growing conditions.

“With the unique mode of action, it's really going to give the growers a nice opportunity to alternate their chemistry. It is very consistent in its performance across Wheat, Barley and Canola."

FMC Southern Regional Sales Manager, Simonne Read excited about Overwatch herbicide released
into wheat, barley and canola this year.

The 2020 Overwatch® Herbicide site at Roseworthy, SA demonstrating the product’s effectiveness in
Canola, Wheat and Barley.

The challenge of keeping Annual ryegrass at bay in a wide range of crops is a continual problem for Andrew Godde, who farms at Culcairn, in the south-east Riverina region of New South Wales.

“Ryegrass is our Achilles heel here,” he said. “Everything else we can manage well but the Ryegrass is the biggest problem facing my farming career.”

He said pre-emergent chemistry is utilised to try to combat the Annual ryegrass early, and last season they utilised the new Overwatch® Herbicide from FMC in a side-by-side comparison trial in Wheat.

“As soon as a new product comes out, we have to jump on it,” he said. “We had Treflan and Sakura, which is of one of the mainstays, and we used Overwatch® Herbicide in conjunction with the Treflan as well, to make it a fair trial.”

“It is all about a numbers game for us. We just don't like to see too many numbers early and it just seemed to me that there were a lot less numbers compared to the other trial plots,” Mr Godde said.

“I was impressed with it all year, the plots with Overwatch® Herbicide have been cleaner and had less Annual ryegrass. I've particularly liked the way it turns the Annual ryegrass pink, I often drive past in my ute, see the pink and know that it is working. It gives you a bit of peace of mind that your money is working for you."

The trial paddock was sown in the last week of April and the crops had 70 mm of rain in the days that followed. “We were a little bit concerned with the rates of pre-ems that we had down, but we didn't seem to have any dramas,” Mr Godde said. “I'm glad we sowed it when we did."

He said the launch of Overwatch® Herbicide, as a new pre-emergent option, was welcomed and makes it possible to rotate herbicides. “The same products have been used too many times, that’s why we need to see this new technology coming through. There's an old saying, if you are on a good thing, don't stick to it. Try and mix it up a bit."

Overwatch® Herbicide is registered for use on Canola, Wheat and Barley and he said it was likely to be used in their wheat phase.

“We don't just use the same one,” Mr Godde said. “We usually use Sakura and Treflan in the first year after the Canola phase and then we usually use Avadex and Treflan the second year because we don't want to overuse the one product. Overwatch® Herbicide will fit well in our program. We'll be able to use it on the first Wheat and maybe Sakura on the second or vice versa. I'm looking forward to having that different technology there."

A typical rotation for the enterprise is a Canola (Roundup Ready or a TT), followed by two crops of Wheat or a Wheat and Barley and then back to Canola. “It’s usually the second year when we can have a blow out,” Mr Goode said. “Then you are back to Canola and you are back to square one.”

The new Overwatch® Herbicide has been welcomed by Andrew Godde, of Culcairn, NSW for Ryegrass control.

The much-anticipated Overwatch® Herbicide from Agricultural Sciences company FMC, is available this season for control of Ryegrass and a wide range of other weeds in Wheat, Barley and Canola.

FMC Technical Extension Specialist, Stephen Pettenon said Overwatch® Herbicide had been in trials and demonstration plots over several seasons and was proven to be robust across a wide range of conditions.

Importantly, it has activity on a wide range of weed species including many that are challenging WA agronomists and growers.

Overwatch® Herbicide is registered for the control of Annual ryegrass, Bifora, Hog weed/Wireweed, Lesser loosestrife, Silvergrass and Sowthistle. It also provides suppression of Barley grass, Bedstraw, Brome grass, Capeweed, Phalaris, Prickly lettuce, Wild oats and Wild radish.

Mr Pettenon said Overwatch® Herbicide had been showcased alongside industry standards and included in a range of tank mixes to help growers determine the best option for their weed spectrum.

With an alternative mode of action compared to other commercial broadacre herbicides, FMC’s new herbicide is an excellent option to use for resistance management.

“Overwatch® Herbicide is unique because the active ingredient is a Group Q, up until now we haven't had a Group Q that's available for use Wheat, Barley or Canola.”

“In areas where Overwatch® Herbicide has been applied, ARG emerges as bright magenta colour. That's a function of the carotenoid being removed and the light basically oxidising all the green tissue. It actually goes pink, then it goes white and then it withers and dies."

He said crops such as Canola, Wheat and Barley have the capacity to metabolise the product and grow through, whereas a wide range of weed species do not.

Overwatch® Herbicide was initially considered because of its activity on Ryegrass, Mr Pettenon explains. “Australian producers spend more dollars controlling that particular weed than all other weeds combined. We’re really struggling with Ryegrass in our intensive system and resistance is a big issue. Coming out with a new mode of action and a new option is great news for everyone.”

The half-life of the active ingredient in Overwatch® Herbicide is a lot longer than other products and has demonstrated excellent residual activity for up to 12 weeks. Mr Pettenon said later germinating Ryegrass in the inter-row continue to turn pink well into the season.

“Ryegrass is an amazing beast. It can come up over a wide germination window, and we've seen that in our trials. Most other products run out of puff early but with the Overwatch Herbicide®, you can see a late emerging weed showing symptoms, and then control. This is a real positive for the product."

He said the recommended application of Overwatch® Herbicide is via Incorporated By Sowing (IBS) with the seed placed sufficiently away from the herbicide.

“The mode of action of Overwatch® Herbicide does not affect any cell division or any cell metabolism like other modes of actions so the seeds that you put in the ground will come up and the vigour is very strong. If the seeding depth isn't right, or if you've got unplanned or unwanted furrow fill, then you will get uptake of the chemical by those plants.”

“This can be expressed by the loss of green tissue or bleaching on some of the leaves. When it occurs, the effect is transient and the plant recovers.

“A lot of work has been done monitoring how the crop recovers and how the crop yields. It is happening at a very early stage of the plant's development and the work that we've done suggests that there isn’t any effect on yield.”
Mr Pettenon said it was exciting that Overwatch herbicide was now available, and it was important to look after it for resistance management.

“New actives don’t come along very often so Integrated weed management in line with the six principles of Weed Smart are recommended.”

Stephen Pettenon inspecting the excellent efficacy of Overwatch® Herbicide at the Geraldton WA trial site.

A new pre-emergent herbicide available for Wheat, Barley and Canola looks an exciting option for Elders agronomist Peter Watt, at Cowra, in the central west of New South Wales.

Mr Watt said the new Overwatch® Herbicide offered an alternative to the chemistry they have been using on the different crops.

“The cropping system was based on trifluralin. We've had it for nearly as long as I've been in this game,” Mr Watt said. “We’ve now moved into the more soluble products and our system has changed. We've gone more to a direct drilling system. We might be looking to retain stubble, so we're looking for other attributes in our soil chemistry to work with our cropping system."

He said pre-emergent chemistries were vitally important with the rate of herbicide resistance and the variability in the seasons.

“If you get a wet year, your post-emergent pass is not guaranteed, or it could be delayed or compromised. The simple fact is the post-ems aren't working. We've got to rely on the pre-em package."

Overwatch® Herbicide was first trialled by Elders Cowra in the dry season of 2018. Overwatch® Herbicide controls susceptible weeds by disrupting photosynthesis, which turns it pink and bleaches the plant before eventual death.
“In Canola and Wheat trials, Overwatch® Herbicide was very visual” Mr Watt said. “What impressed us most is that we rely on a couple of things with weed control, efficacy of the product but then the host crop has got to impart really good competition. You don't want the herbicide knocking the crop too much because it's about competition and efficacy of your product."

“We really did see the efficacy of Overwatch® Herbicide. It was still paying out a long time after some of the other products had given up the ghost."

Overwatch® Herbicide is registered for the control of Annual ryegrass, Bifora, Hog weed/Wireweed, Lesser loosestrife, Silvergrass and Sow thistle. It also provides suppression of Barley grass, Bedstraw, Brome grass, Capeweed, Phalaris, Prickly lettuce, Wild oats and Wild radish.

“You don't have to step too far before you see Annual ryegrass, so it is pretty much endemic here,” Mr Watt said. “What is also endemic is Group A and B resistance and, in some cases, multiple resistance.”

He said there were also challenges with weeds such as Black oats (Wild oats), Barley grass, Silvergrass, Wild radish and others which are all on the Overwatch® Herbicide label.

“For Ryegrass control, Overwatch® Herbicide is up there with some of the other market leaders. We’re seeing mid-eighties up to mid-nineties in weed control."

Mr Watt said the three crops on the label provided flexibility and gave options for growers. “I particularly like Overwatch® Herbicide in the Barley market, but it doesn't lock it in to the Barley market,” he said. “It will find some space in Wheat, and we'll be utilising it in Canola.

To take broadleaves out of Canola has been a tricky situation unless we default to the triazine chemistry or the increasingly unreliable Clearfield chemistry. Overwatch® Herbicide is a lovely complement in that Clearfield space, also in the TT space and in non-herbicide tolerant Canola. In Wheat, and Barley, it gives us a lot of flexibility."

“There's a broad spectrum of weeds in there. I think we'll learn a lot more about this product over the next couple of years as it gets out into the commercial space."

Peter Watt, of Elders Cowra, is excited about the opportunities for Overwatch® Herbicide in Barley, Canola and Wheat.

A new tool to combat the growing challenges of weed resistance has been welcomed by agronomist Ian Koch, at J & D Southwood, on the Yorke Peninsula of South Australia.

Mr Koch said most of the farmers in the region were continuous croppers and have a high degree of herbicide resistance through their paddocks.

“The northern Yorke Peninsula is particularly noted for its ryegrass resistance to trifluralin ,” he said. “Most guys have got Group A resistance and there's a reasonable amount of Group M and Group B resistance. Glyphosate (Group M) resistance is coming off the fence lines and moving into the paddocks.”

“There was long history of Glean and Logran in the 80s and now we use a lot of imi's because of the weed spectrum. Most guys are aware of it and are looking at changing products around to keep all the tools in the shed for longer. We've only got the pre-emergent products that do a good job. The post-emergent products are really struggling.”
Last season Mr Koch visited a number of trials to view FMC’s new Overwatch® Herbicide, a Group Q pre-emergent herbicide registered for use in Wheat, Barley and Canola to control Annual ryegrass and a wide range of other weed species.

“This was the third year we've been aware of it and had a look at trials,” Mr Koch said. “Overwatch® Herbicide is another tool to extend the life of current products. It gives us the opportunity to be selective about where we want to use it, we don't just have to go and put it over everything like we have done previously.”

Looking at how Overwatch® Herbicide will fit into his program, Mr Koch said, “Bifora is a huge problem for us on the Peninsula and the fact that it smokes Bifora really well is just a bonus that we weren’t expecting. We're happy to have great Annual ryegrass control but the Bifora is a real win for us because it is an ongoing problem."

He said Overwatch® Herbicide provided a chance to look at the farmer’s rotation and also mix with other herbicides to target the specific weed spectrum to get the best result. “I can see Overwatch® Herbicide being used by itself in certain circumstances but also can see a tank mix with some of the other products that are coming out or are in existence.”

Mr Koch visited the Overwatch® Herbicide demonstration site in Roseworthy last season and was impressed by some of the tank mixes. “In Barley, the Overwatch® Herbicide and metribuzin plot was exceptionally clean for not a huge increase in cost. That's something I would be recommending to a few guys on the coastal country that grow Barley. We could use Overwatch® Herbicide in that situation as it has a much better resistance strategy for Brome grass.”

He said the Overwatch® Herbicide and Callisto® herbicide mix was also one that stood out. “I gave a nine and a half out of ten for the Broadleaf and nine and a half out of ten for the Annual ryegrass control. It has done a fantastic job and I hadn't previously considered it as a serious option.”

“With that sort of weed control, I really have to sit down and have a good look at it and do the sums.”

The ability of Overwatch® Herbicide to be available across the three major Winter crops also adds flexibility in times of crop failure or change. “We can grow Wheat, Barley or Canola, so if you had a bad snail or slug problem or something went wrong at least you could put something back on it,” Mr Koch said.

He said it was important to ensure new chemistry is utilised well, which also allows the lifespan of existing options to be increased. This includes mixing and rotating herbicides, and always using the full label rate of Overwatch(R) Herbicide.

“Everybody knows that in the chemical market it is getting harder to produce new products. We should try to keep our existing products and also look at mix options. That is going to be better for everybody."

Ian Koch, of J & D Southwood, sees a great fit for Overwatch® Herbicide in a range of crops and as a tank mix to help control a wider weed spectrum.

Overwatch® herbicide, from FMC, has officially been registered and will be available for the 2021 winter cropping season as a control for annual ryegrass and a wide range of other weeds.

FMC Herbicide Product Manager, Hugh Palmer, said the herbicide had been extensively trialled over many seasons and was now available as a pre-emergent option in wheat, barley and canola.

“This is a really unique herbicide,” he said.  “Overwatch has control over Annual ryegrass and weeds such as silvergrass, bifora, sowthistle, hogweed and lesser loosestrife.”

He said Overwatch was initially assessed as an annual ryegrass product because of the concern regarding that weed in winter cropping regions throughout Australia

“It has outstanding annual ryegrass control and the fact that it effectively controls a wide range of other species is a real bonus.”

“There are a large number of weeds registered for suppression on the label so this herbicide will have an excellent fit in many paddocks,” he said.

“Overwatch also has long-lasting residual control making it very effective on later germinating weeds.  Up to 12 weeks control of a wide range of species has been demonstrated.”

He said Overwatch is a Group Q herbicide, making it unique in the Australian broadacre market.

“Registration is very timely, as many of the weed species are developing resistance to commonly used herbicides.”

“The use of Overwatch in a winter crop system will help take the pressure off herbicides that are struggling with resistance.  It also has the ability to control weeds that are no longer susceptible to other options.”

Mr Palmer said the unique mode of action certainly had growers and agronomists taking note as the ryegrass germinated and turned a bright magenta colour before perishing.

“Overwatch herbicide works by inhibiting the production of carotenoids in susceptible plants,” he said.  “This, in turn, affects a plant's ability to produce energy through normal photosynthetic pathways. While the crop is able to metabolise the herbicide, the susceptible weeds use up available energy from the seed and then die.”

Overwatch is applied as an IBS (Incorporated By Sowing) treatment and has demonstrated its robust performance across a wide range of locations and conditions.

“Trials have been conducted across all the major winter crop areas of Australia and have included testing in a wide range of soil types, stubble loads and moisture conditions,” Mr Palmer said.

“The efficacy of Overwatch has been outstanding across the different environments.  It has consistently demonstrated really good control of weeds.”

He said because Overwatch was registered in three key winter crops it provided greater options for crop rotations.

“Residual herbicides have been challenged with dry conditions in recent years so the introduction of Overwatch means growers can have more flexibility with the following crop.”

Crop safety was an important aspect of achieving registration and many trials have been conducted to demonstrate the ability of the crops to metabolise the herbicide and continue to grow.

“Some pre-emergent herbicides affect cell division and that may limit the crop’s root or plant growth,” Mr Palmer said.

“The effect is not seen in Overwatch and the only sign of the herbicide being metabolised is a transient bleaching of the crop.

“Discolouration is not common and is normally associated with higher doses of herbicide contacting the seed or plant directly.”

“Symptoms are negligible within weeks of the first appearance and the plants continue to actively grow throughout the process.”

The recommended application of Overwatch via Incorporated By Sowing (IBS) helps ensure the seed is placed sufficiently away from the herbicide.

Now that registration was achieved, FMC were producing good volumes of Overwatch herbicide in preparation for the 2021 season.

There are many trial sites throughout Australia in 2020 that are available for inspection by growers and agronomists.”

“I would encourage interested parties to have a look at the performance of this unique herbicide and see how suited it is to current farming practices,” Mr Palmer said.