Cereals 2009: Blackgrass control difficult without key post-emergence products

It would be difficult to get even 90% control of blackgrass year-on-year, without the use of Atlantis or fop/dim herbicides, Jim Orson of The Arable Group said.

An HGCA-funded project had looked at control programmes without those two key herbicide groups, and found that achieving 90% control was difficult, he said.

“To get that 90% control you need a low population to start with.”

Using Atlantis was one way growers could potentially reduce populations to a low enough level to get decent control without it, he suggested. “It is perhaps then you need to be brave enough to stop using Atlantis, and look at these alternatives, to enable you to save Atlantis for when you might need it.”

The key herbicide active ingredient in non-Atlantis programmes was flufenacet, he said, with the most successful option in the trials being a sequence of Liberator (flufenacet + diflufenican) and Crystal (flufenacet + pendimethalin).

That delivered 480g/ha of flufenacet, which was marginal for crop safety, he said. “It is something you can do legally, but it is not really in the spirit of the law [as it applied a higher dose of flufenacet than was legally allowed to do with either product alone].”

It also had to be a sequence and not a tank-mix to remain on the right side of the law. “But the danger is if you use flufenacet every year that there could be a decline in performance, as has been seen in pot tests.”

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