New herbicide offers fresh blackgrass control option

A new Atlantis-plus herbicide from Bayer claims to deliver better blackgrass control.

The herbicide will be available this autumn for winter wheat growers troubled by the yield-sapping grassweed.

Called Hamlet, this post-emergence product is said to give up to 10% better blackgrass control than Atlantis by adding a residual herbicide to the mix.

By adding the widely used diflufenican to a remixed Atlantis formulation, a 5-10% better control of blackgrass and improved control of some herbicide-resistant blackgrass can be achieved, the group said.

See also: Growers need to react now after bad blackgrass year


  • Atlantis – mesosulfuron + iodosulfuron
  • Hamlet – mesosulfuron + iodosulfuron + diflufenican
  • Liberator – diflufenican + flufenacet
  • Defy – prosulfocarb
  • Stomp – pendimethalin

The product is set to take over from Atlantis for autumn use and will be priced to reflect the extra diflufenican on an average price of Atlantis of about £37/ha, while a new Atlantis formulation for the spring is set to be available over the next few years.

Andrew Orme, Bayer Crop Science’s UK managing director, says this will reinforce Bayer’s strong position in herbicides and comes after a gap from the launch of Atlantis in 2003 and Liberator in 2004.

“It is more difficult to develop new herbicides than fungicides and insecticide as there is the extra problem of weed resistance,” he told a launch briefing.

Market share

This comes as Bayer’s share of the annual UK arable agrochemical market of £800m reaches 32%, up from 18% some 10 years ago, helped by the success of Atlantis and Liberator and fungicides Aviator and Proline, putting the group ahead of BASF and Syngenta.

Ben Coombs, group herbicide product manager, said a good programme using Hamlet should give 95% control of blackgrass, which is a level when the weed should not get any worse in subsequent seasons.

“Hamlet offers a step up in control compared with Atlantis, which is really important when growers are looking to manage blackgrass populations,” he added.

The addition of the residual diflufenican to Atlantis’ contact components mesosulfuron and iodosulfuron is seen by the group as the first big improvement in post-emergence grassweed control since Atlantis was launched in 2003.

Extra residuals

Mr Coombs said a classic combination of pre-emergence Liberator followed by Atlantis has been seen to give 80% control of blackgrass, and the use of Hamlet and adding other residuals to Liberator can give up to 95% control.

As Hamlet is best applied early, there is potential for subsequent germination of blackgrass after the application, so it is advised to mix Hamlet with a residual partner, for example a flufenacet-based product such as Liberator or other products such as Defy or pendimethalin (such as Stomp).

Because Hamlet and Liberator both contain diflufenican, care should be taken not to apply excessive rates, and if a high rate of Hamlet is used, ploughing or cultivation to 15cm is required if the following crop is oilseed rape or sugar beet.

The best timing for Hamlet will be from November to the end of February, when the blackgrass is at the early one- to three-leaf stage and before it tillers. The product also gives better control of ryegrass and bromes than Atlantis, and a wider spectrum of broad-leaved weed control.

Gordon Anderson-Taylor, group development manager, suggests if Liberator is used with one or two other residuals, and drilling is delayed until 15 October, any surviving blackgrass will be so weakened that Hamlet will give good control.

Weed resistance 

As Hamlet is based on the same actives as Atlantis, blackgrass with acetolactate synthase (ALS) target-site herbicide resistance will continue to have resistance to Hamlet, but it could give better control of another form of resistance.

“Our trials show that early application gives you an improvement against blackgrass with enhanced metabolism resistance [EMR] – the most common type of resistance in UK blackgrass,” he said.

Mr Coombs suggested growers should ensure chemistry programmes are diverse and highlighted that key products for blackgrass and ryegrass control are glyphosate, Liberator and Hamlet.

“None are immune to resistance, but as they are in different chemical groups, they will protect each other,” he added.

The herbicide option should only be used as part of a complete control programme including ploughing, delayed drilling, low-disturbance cultivations, high seed rates and spring cropping, Mr Coombs added.

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