Spring clean-up choice looks simple

IF YOU are still waiting for suitable weather, soil conditions or the correct weed growth stage to finish, or even start, your grassweed herbicide programme, Atlantis is the main, and perhaps only, choice for blackgrass control this spring, most agronomists agree.

Many growers who applied pre- or post-emergence autumn treatments are satisfied with results, they report. But estimates on the unsprayed area vary.

“All my crops have had something,” says Essex-based Andrew Blazey of The Arable Group. “It was a good, open autumn.”

Beds-based ProCam technical director David Ellerton agrees. “Very few crops have had nothing,” he says. “Now we”re waiting to see what needs a follow-up.”

Further north, though, Lincs-based H L Hutchinson technical manager Dick Neale suggests as many as 40% of fields may not have been treated – more than he likes to see. “Most are later-drilled fields, where growers could not get on or where they have taken a conscious decision to wait and apply Atlantis.”

Large blackgrass is his concern. “It has been an open winter, so there are blackgrass plants with multiple tillers,” he says. “Atlantis is the best choice, unless Bayer gets approval for the 500g/ha rate of 05H [an alternative formulation of mesosulfuron-methyl + iodosulfuron-methyl-sodium], which would give extra options for bigger blackgrass plants.”

Where no residual base has been laid, Atlantis alone is not supported because of increased resistance risk, warns Mr Neale.

“Stomp will be the tank mix partner more often than not, but mixes with Hawk to give two shots of contact is a viable option, too.”

Bigger blackgrass might test Atlantis more this season, suggests Agrovista’s Mark Hemmant. “There’s more risk of enhanced metabolism the bigger the blackgrass. Atlantis might not do quite such a good job as last spring.”

Atlantis resistance management concerns Mr Blazey. “I plan to avoid using it two years running on the same field.”

About 70% of his fields had an autumn pre-emergence spray, and only 5-10% have not yet been followed up. Most blackgrass was too small to receive Atlantis, so growers looked for something else to hold it, he says. “Gallons more IPU was used last autumn. If IPU does go, we would miss it.”

Good pre-em treatments have worked exceptionally well, notes Mr Hemmant. “Some growers may not even need Atlantis this spring, or perhaps only patch spray.”

Where it is required after residuals, provided there is no obvious sign of germination, the product can be used without a residual partner this season. “Lexus is an alternative, but only use it if you haven’t got any concerns about control.”

Always use a clodinafop-partner, such as Hawk, in tank mix with Lexus, rather than Stomp in spring, he adds. “Lexus + Stomp can be a bit warm.”

Dr Ellerton has used autumn- applied Lexus + Stomp on fields with moderate blackgrass levels.

“I knew I could go back with Atlantis if necessary. But in most cases that won’t be necessary, which has saved an awful lot of money.”

Sequences of Lexus followed by Atlantis have yet to be approved by PSD, stresses Mr Hemmant. “Until they are, we’re steering clear.”

Once it has been applied there are few other options left. “That”s your last shot,” says Dr Ellerton. “Fops and dims are a total waste of time.”