Could Unite be new tool in blackgrass fight?

Dow AgroScience’s newly named herbicide Unite had its debut as GF2070 last year. Louise Impey asks some agronomists how it fared

Unite proved to be extremely effective against brome last season for an Essex agronomist, even where the weed had reached quite a size.

Rory Clark-Kennedy of Strutt & Parker tried 100ha of the product, targeting it at situations where brome was the main concern, but where blackgrass was also present. Both autumn and spring applications were used, giving him a good introduction to the herbicide and the chance to compare it with market alternatives.

“I’ve got two blocks of land where, for a number of reasons, I didn’t want to use Atlantis,” he explains. “So the opportunity to try the new product was too good to miss.”

On one block he applied full-rate Crystal at the pre-emergence timing, following up with a Unite/Defy mix in mid-November. “And it worked very well, even round the headlands,” he says. “We only had to go back to chase a few broad-leaved weeds.”

Results from Atlantis in the previous year had been disappointing. “The two products are very similar in cost, so switching from one to the other was straightforward. It also allowed us to make use of different active ingredients and give Atlantis a rest.”

Unite was applied at a rate of 0.27kg/ha, with Defy at 2 litres/ha.

On another 50ha block Unite was applied in the spring, in early to mid-February, after a pre-emergence treatment in the autumn. “Again, brome was the main target, but other grassweeds were present too.”

No further action was required after spraying, not even for broad-leaved weeds. “It gave us a complete tidy-up, even against decent-sized brome,” he says. “So it performed very well and met our expectations.”

Mr Clark-Kennedy’s challenge for the coming season is whether to pitch Unite against really bad blackgrass.

“My instinct is to give it a go, especially where Atlantis seems to be having difficulties,” he says. “I can swap them over quite easily, as both should be used when blackgrass is up to the two-leaves stage.”

But he admits to being more wary about using Unite where blackgrass is the sole target and proving difficult to get on top of with planned programmes. “It would be a case of trying some and comparing it with others, rather than jumping in with both feet.”


Atlantis – iodosulfuron + mesosulfuron

Broadway Sunrise – pendimethalin + pyroxsulam

Crystal – flufenacet + pendimethalin

Defy – prosulfocarb

Unite – pyroxsulam + flupyrsulfuron

In Hertfordshire, independent agronomist David Nicholls used Unite and Atlantis in the same field so he could do a side-by-side comparison.

Blackgrass and brome were the target weeds. “The field was drilled in awful conditions and the blackgrass was up and growing before the wheat crop. So it was a stern test.”


He was pleased with the results from both products, having assessed them throughout the year. “It was a difficult season and they performed well.”

But the Atlantis did a better job on the blackgrass, he says. “In contrast, Unite did an exceptional job on the brome.”

Spring applications were also tested. “Unite didn’t fare as well at this timing, but the Atlantis did better than it did in the autumn. So we’re still learning about the best conditions for the application of these products and the influence of seasonal factors.”

As a result of his experience, he sees Unite as another option where mixed populations of grassweeds grow.

“Atlantis has still got the edge where blackgrass is the main problem. But of course that may not be the case for much longer. It could be that Broadway Sunrise is the better pyroxsulam choice for blackgrass.”


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