United Kingdom
November 20, 2014
The next two weeks are ‘crunch time’ for the battle to control black-grass in this year’s wheat crop, Bayer CropScience has advised growers.
Reporting on monitoring from its field team, the Atlantis WG (mesosulfuron + iodosulfuron) manufacturer says a largely successful pre-emergence campaign based on a variety of flufenacet products has delivered ‘excellent’ control so far. But it’s warned that waiting until spring to resume the control programme could allow the weed to gain an unwanted foothold in many crops, a position backed up with the release of new independent trials data.
“The success of this year’s pre-emergence campaign has highlighted the wisdom of those who waited to drill, rather than rushing in too early,” says Ben Giles, a commercial technical manager with Bayer CropScience. “Applications made during the early part of September, typically applied to drier soils, have certainly seen higher instances of disappointing control of black-grass than later drillings”.
Rain in late September and during October, meanwhile, has been the reward for those patient enough to have drilled later, he notes. “The later applications of pre-ems – often stacked – have produced some really good results.”
But mild weather and continued rainfall is now making conditions ideal for black-grass growth, says Mr Giles.
“Give black-grass an inch and it will take a mile; you get no second chances. If it’s looking sickly but might survive the pre-em, don’t give it a chance to recover but follow up with an effective post-emergence herbicide such as Atlantis WG.
“It’s worth putting in the spend,” says Mr Giles, pointing to Atlantis WG plus a good, strong residual like 0.3 L/ha Liberator (flufenacet + diflufenican), prosulfocarb-based products or pendimethalin/picolinofen formulations. If choosing 0.3 L/ha Liberator, Mr Giles says it’s important to remember to ensure a gap of six weeks since the pre–em if that was based on 0.6 L/ha of Liberator.
“If this application is missed or you wait to allow the black-grass to recover, you’re going to be faced with spring black-grass that’s just too well established for herbicides to control. Not only will you be sacrificing yield, but you’re also running the risk of encouraging resistance to take hold in that black-grass population.”
Trials conducted during the 2013/14 season by independent contractors showed that spring applications of Atlantis WG made at GS23-25 gave a 29% drop in efficacy – control of less than 60% - compared to those made in autumn at GS11-13 (1 – 3 leaves).
2014 trials conducted by independent contractors and distributors showed that autumn is the time to be thinking about post-emergence herbicide applications. Ten UK trial results. Pre-em applied, Liberator 0.6 L/ha or Liberator 0.6 L/ha + prosulfocarb at 2 L/ha. Atlantis WG applied at 0.4 Kg/ha + biopower 1 L/ha + Liberator 0.3 L/ha.
“Over the next two weeks be sure you’re keeping a close eye on what’s happening in your crops, and be ready to make that Atlantis WG application whenever the weather window appears, even if that means only one tank-load a day,” concludes Mr Giles.
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