With a label extension creating more flexibility for ethofumesate’s use in winter wheat, the herbicide is proving a valuable mix partner as growers strive to tackle difficult grassweeds. CPM takes a closer look at Xerton.
“Xerton performs well as a pre-emergence residual treatment because it targets weeds via shoot uptake as they push through the soil surface.” NIGEL SCOTT
By Janine Adamson
Ethofumesate – historically regarded as a staple, cost-effective tool for grassweed management in sugar beet. However, following a recent label extension, the herbicide is starting to find a firmer footing in winter wheat crops too, particularly when it comes to controlling blackgrass and brome.
While Xerton (ethofumesate) has been authorised for use in winter wheat since 2015, this was limited to post-emergence only, despite trial work suggesting it was most effective when used at pre-emergence timing, explains UPL’s Tom Wheelhouse.
Now, with pre-emergence use under its belt for a year, he believes this truly opens up a window of opportunity for growers. “Undoubtedly, it works best at pre-emergence stage of the grassweed, prior to the formation of the waxy cuticle. While there’s limited activity when the weed is just emerging at the little green stick phase, as soon as a leaf is out, the activity drops off,” he adds.
Critically, it’s what Xerton adds to a tank mix that should pique the attention of growers now it can be used at pre-emergence, believes Tom. “Trials indicate Xerton offers around 8-10% uplift to a pre-em herbicide stack when it comes to controlling blackgrass.
NEW ADDITION
“For a lot of growers, that’ll be relatively consistent, as ethofumesate isn’t an active they’ll have used on heavier land because crops like sugar or fodder beet don’t feature in the rotation. Of course, where grassweeds have been exposed to the active, performance will likely be reduced somewhat,” he comments.
Tom adds that with pre-emergence on its label, suddenly Xerton is a far more compelling option. “If we look at other active ingredients used at this timing, although ethofumesate is in HRAC Group 15 therefore the same as the likes of tri-allate and flufenacet, it belongs to a different family within that group.
“It behaves differently, which means as well as offering an uplift in control, it’s contributes positively to resistance management across the entire weed control programme. Equally, this further strengthens its position as a go-to tank mix partner to protect those critical, premium actives,” he explains.
To help affirm this, Tom raises that work is currently taking place to explore and quantify ethofumesate’s mode of action in practice. “It might be an older product, but it has a new use, so therefore we want to fully understand its mechanism to reinforce its position and instil trust.”
As well as offering valuable activity against blackgrass, Xerton also controls brome, highlights Tom, and is active against all species. “For sterile and great brome, it’s a useful partner to add to the pre-emergence stack. For spring-germinating bromes it’d be preferable to hold applications back to be post-emergence of the crop, although still pre-emergence of the brome,” he advises.
The role of Xerton in brome control is something that agronomy company ProCam has been exploring following continued uncertainty regarding the long-term future of flufenacet. After the European Commission’s non-renewal of the active ingredient in the EU and Northern Ireland in March 2025, fears remain that UK authorities may follow suit in due course.
With that in mind, ProCam has conducted trials to seek alternative options, with Xerton offering promising results in the context of soft brome. Agronomist and northern region technical manager Nigel Scott says preliminary observations suggest that despite established blackgrass herbicides such as cinmethylin and/or flufenacet forming an important element of brome control, additional molecules and modes of action are also required.
“Xerton performs well as a pre-emergence residual treatment because it targets weeds via shoot uptake as they push through the soil surface. I’ve used Xerton in conjunction with 2.0 l/ha of Tower (chlorotoluron+ diflufenican+ pendimethalin) to good effect against brome, which can be difficult to control at the best of times. Having Xerton at pre-em certainly stands out as a useful addition to the crop protection armoury.”
Nigel highlights that Xerton’s new flexibility should give a good level of reassurance for growers who’ve faced a few autumns of early drilling and dry seedbeds. “Flexibility for products to be applied either pre- or post-emergence is key to allow chemistry to be deployed at the most effective time.
“Last year, we saw in ProCam trials that when crops were drilled early, delaying applications of the most potent chemistry helped to improve weed control; with a pre-emergence herbicide chosen with activity in dry conditions. Where there’s moisture however, or where drilling is more usual or delayed, the strongest chemistry should be applied first.
“Xerton now fits either scenario, meaning farmers don’t have to change the product choice if the season or weather changes planned approaches,” notes Nigel.
ProCam’s southern regional technical manager, Paul Gruber, has also been trialling Xerton in herbicide programmes. “Where I’ve used Xerton as a tank mix partner with robust pre-emergence actives such as cinmethylin, it’s certainly packed a significant punch against blackgrass.
COST-EFFECTIVE
“In fact, I’d go so far as to say that a pre-em treatment of Xerton plus Agardia (cinmethylin+ picolinafen) performs on par with Avadex (tri-allate), and at a much lower cost point.”
Paul agrees that for brome, Xerton is preferential to flufenacet, but warns that timing is essential to avoid crop effects. “Peri-emergence application must be avoided,” he stresses. “Also, Xerton isn’t a direct replacement for flufenacet as it’s ineffective against ryegrass. That said, it’s certainly a promising addition to the herbicide stack in other scenarios, and I’ve seen good results when it has been used later in the autumn to top-up pre-emergence treatments,” he says.
Tom highlights that as with other grassweed herbicides, Xerton also offers a level of broadleaf weed control, particularly chickweed and cleavers. And while in-field conditions are currently exceptionally dry (mid-August), another benefit of the product is its soil persistency.
“In-house observations indicate it’s active within the soil for around 8-10 weeks post application, which is particularly helpful in catchy conditions,” he says.
This article was taken from the latest issue of CPM. Read the article in full here.
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