On a par with Atlantis. That’s the claim being made by Dow AgroSciences about Broadway Sunrise for post-emergence blackgrass control, ahead of the new cropping year.

Originally launched in 2010 for use on mixed grassweed populations where blackgrass was not the main problem, the pyroxsulam-based herbicide is now being marketed as a solution for blackgrass situations.

Grower and distributor feedback, together with further independent trials results, have given Dow AgroSciences the confidence to recommend Broadway Sunrise for blackgrass, explains Vaughn Stansfield.

“As well as its very good blackgrass activity, it offers the cropping and cultivations flexibility, crop safety and tank-mix compatibility that others don’t,” he says. “It can be used in the autumn or the spring and has good control of other grass and broad-leaved weeds.”

Autumn applications are preferred and will give the optimum performance, confirms his colleague, Stuart Jackson. “Best results come from a 3.5 litres/ha treatment at the one to two-leaf stage, when the blackgrass is actively growing, at a water volume of 130-150 litres/ha and a medium spray quality.”

Furthermore, Broadway Sunrise must be used in a programme with a pre-emergence herbicide which supplies a minimum of 240g of flufenacet/ha, he says.

“The pendimethalin content of Broadway Sunrise means that Crystal can’t be used ahead of it. But Liberator or Movon/Vigon are fine, as are Defy mixes. It’s only products containing pendimethalin that you have to be wary of, to avoid exceeding the 2,000g limit.”

Where the right pre-emergence and Broadway Sunrise programme is used in the autumn, growers can expect 92-93% control of blackgrass, reports Mr Jackson.

“Used in this way, it has consistently performed on a par with the market standard. Of course it is an ALS inhibitor, so if you have known ALS target-site resistance, the weed population will be resistant to Broadway Sunrise.”

Dave Robinson of Frontier Agriculture warns that the one to two-leaf stage is a narrow window, making the application timing tricky. “The question in my mind is: what happens if you can’t spray until the blackgrass is at three leaves and one tiller?”

Adding pendimethalin does enhance herbicide performance and is more effective when sprayed very early, he adds. “So it is reasonable to believe that it works very well at this timing. But I haven’t seen any work which shows that it’s better than stacking pre-emergence residuals and then following that up with Atlantis.”

NIAG TAG agronomist Jon Bellamy points out that results with Broadway Sunrise against blackgrass were better than expected last year, making him wary of Dow AgroScience’s claims at this stage. “We need to see more data before widespread use of it on bad blackgrass populations.”

He will still be using Atlantis, aiming for the early post-emergence timing and mixed with something to help control plants with enhanced metabolism resistance. “However, there’s no doubt that Atlantis is fading, especially after the third use in the field.”

Dick Neale, technical manager with Hutchinsons, reveals that the company’s results with Broadway Sunrise against blackgrass have always been impressive, but adds that the best performance comes from paying close attention to application technique. This includes using low water volumes, a fine spray, the right boom height and suitable adjuvants.

The rapid slide in the performance of Atlantis means that Broadway Sunrise is now a viable alternative, he believes. “Unlike Atlantis, it seems to be holding its own. But blackgrass is too big in the spring for contact materials, so growers must move away from spring treatments.”

He favours Broadway Sunrise over Atlantis where there is a mixture of bromes and ryegrass, as well as blackgrass, and stresses the importance of the pre-emergence treatment. “Liberator or Vigon are options, or you could use half-rate Liberator with half-rate Crystal.”

But Mr Neale cautions growers about its earlier cut-off dates. “It is more affected by a rapid drop in temperature than Atlantis. The weeds must be growing well for it to work.”

He also believes that Atlantis is a better bet for spring applications. “However, it can be harsh.”

Price-wise, Broadway Sunrise is very similar to Atlantis plus pendimethalin, he calculates.

Spring applications

Spring applications of Broadway Sunrise also give similar results to Atlantis, says Stuart Jackson, although both products lose five to six percent of control when used at this timing.

“The variability is also much greater with spring treatments. That’s why the optimum is an autumn spray.”

Unlike Atlantis, Broadway Sunrise can only be used up until GS29 in the spring, he says. “In the autumn, our advice is to use it up to early tillering, or GS24.”

Actives

Atlantis – iodosulfuron + mesosulfuron

Broadway Sunrise – pyroxsulam + pendimthalin

Crystal – flufenacet + pendimethalin

Defy – prosulfocarb

Liberator – diflufenican and flufenacet

Movon/Vigon – diflufenican + flufenacet + flurtamone