THINK CAREFULLY about broadleaved weed control options this spring if you applied grassweed killer Atlantis in the autumn, warns Hutchinson’s technical manager Dick Neale.
“Using sulfonylureas to clear up any broadleaved weeds used to be easy. Now you’ve got to think about it and plan more carefully.” That’s because using a second sulfonylurea, if approved, after Atlantis will prevent sowing oilseed rape as a following crop, he says. “With the single farm payment, growers are looking to grow wheat/oilseed rape rotations in ever increasing areas.”
For those wanting to sow oilseed rape, using products such as Starane XL or Hiker will likely be out of bounds if they have used Atlantis despite their recent sequence approval, he believes.
“Only cereals can be planted following an Atlantis/florasulam-containing product sequence as it stands. Although that is a dynamic situation.”
Autumn applications of Atlantis are more likely to need over-spraying for broadleaved problems than spring ones, he says. “A spring application of Atlantis, particularly with a residual partner is likely to control most broadleaved weeds.”
Growers do have other non-sulfonylurea broadleaved control options if needed, he says. “But they need more planning.”
Cleavers are likely to be the main target. “Growers can apply Starane 2 or the sulfonylurea Eagle,” he says. The latter does permit oilseed rape to be sown. “But it doesn’t control a very wide range of other weeds.
“Starane controls cleavers easily, but is later applied, so you may not maximise yield.”
Hormone herbicides, such as MCPA, 2,4D, dicamba, CMPP and HBN’s, will clean up specific weeds left after Atlantis, but growers should choose carefully.
“Individually, they don’t necessarily control the broad range of weeds, like sulfonylureas, and the cut-off date for application is much earlier at GS31-32.”