Think carefully about using an especially robust anti-blackgrass herbicide programme on this autumn’s wheats. Only where the weed is particularly rampant should it be necessary, says a southern agronomist.
One who does advocate such an application, of Atlantis plus a flufenacet-based residual like Liberator or Crystal, soon is UAP’s Jo Bell.
Plenty of crops never received a pre-emergence treatment mainly because of poor seed-beds, she explains. “The proportion varies around the country but in many places the seed-beds were too cobbly.
“Often growers are still waiting for the crop to come up after the blackgrass, and in some fields the blackgrass is so bad that we’ve not much option.”
Steve Cook of Hampshire Arable Systems is unconvinced that Atlantis is necessary yet except in exceptional cases.
“We’re not seeing much blackgrass pressure so far. Drilling was generally later this year and there is definitely more dormancy. The plants are smaller and it’s getting colder so they’re growing more slowly.”
Growers spraying Atlantis too soon in that scenario could deny themselves the chance to use it more effectively later on. There may be plenty more blackgrass to tackle before long after recent frosts opened up seed-bed clods, he reasons.
“I have only one field on one farm, on Weald clay, where the blackgrass is at two to three leaves and needs a contact spray.”
His preferred option is to apply Crystal or Liberator topped up with isoproturon to add some contact action when the blackgrass is at the one to two leaf stage.
“I’d rather keep Atlantis in the bag for later.”
Patrick Stephenson, fellow AICC member, in Yorkshire agrees, even though his applied pre-em treatments were 50-60% less than planned.
“There’s a lower flush of blackgrass than normal, probably because of the later sowing, and we’re unlikely to get much Atlantis on this side of Christmas.
“It’s a bit of a misconception that a lot of blackgrass comes through in the spring. But there are plenty of other grassweeds, like brome, that do and, quite apart from the cost, I like to keep the Atlantis for those.”
Andrew Cotton in Oxfordshire, also AICC, echoes those views.
“There’s certainly less blackgrass about. It varies from farm to farm, but a lot of people got on quite well with their pre-ems, especially on the early drillings.”
Treatment decisions on later sowings struggling against slugs are undecided, he says. “We want to make sure we have a crop first!
“Boxworth work suggests there is still a lot of blackgrass to come through.”
So for the few crops that do now require Atlantis adding a good residual is important, says Mr Cotton.