Growers with severe blackgrass problems are still waiting to hear if a potentially knock-out herbicide sequence will be officially approved.

No decision has yet been made by the Pesticide Safety Directorate on the sequence of two highly active blackgrass weed killers, Lexus (flupyrsulfuron-methyl) and Atlantis (mesosulfuron-methyl + iodosulfuron-methyl-sodium), owing to concerns about the build-up of resistance to the chemical class.

Distributor trials suggest the sequence could be very effective.

The wider implications of such sequences were discussed at a recent Weed Resistance Action Group-organised PSD meeting, says Rothamsted Research blackgrass resistance expert and WRAG committee member Stephen Moss.

“But the focus was on a Lexus-Atlantis sequence.”

No decision was made at the meeting, notes Brin Hughes, technical manager for distributors UAP.

There is a distinct lack of evidence one way or the other about the resistance risk.

I didn’t get the impression it was going to happen suddenly.”