Spring rape growers should look to a soon-to-expire off-label approval to control weeds that have escaped pre-emergence herbicides, says Dalgety's Dr Bob Bulmer. Where performance of Butisan and Treflan has been inconsistent during the dry April he recommends a post-em application of Benazalox up to a rate of 1.0kg/ha, particularly on dry or higher organic matter soils, where he has observed the problem to be most severe.

"Although Benazalox has a fairly limited weed spectrum it takes out key broad-leaved weeds. Where mayweed, chickweed and polygonums have come through there are no other suitable treatments."

Spring rape growers should obtain the relevant paperwork before applying Benazalox which only has an off-label approval.

"Growers need to be in possession of the relevant SOLA (specific off-label approval) before making any applications; it has been made available via the Dalgety website (www.dalgety.co.uk )."

He added that as usage is off-label approval it is important that advice is sought. Growers should contact their local Dalgety office for advice from a BASIS-registered agronomist. "As the product is being withdrawn this year this opportunity may help growers use up any existing inventory remaining on the farm thus avoiding disposal problems," he said.