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Weed Management

Bayer Crop Science

Get the aclonifen effect in barley

Article overview

Farmers can call on a new mode of action to control weeds in winter barley crops. Bayer now supports Proclus (aclonifen) in a tank-mix with Liberator (flufenacet + diflufenican) for pre-emergence control.


Farmers can call on a new mode of action to control weeds in winter barley crops. Bayer now supports Proclus (aclonifen) in a tank-mix with Liberator (flufenacet + diflufenican) for pre-emergence control. Campaign manager Tom Chillcott outlines what to expect when using it this autumn.”

Improve weed control

“Winter barley can be a challenging crop for weeds. It’s usually drilled earlier than wheat and there are fewer herbicides available, so farmers are far more reliant on good establishment and effective crop competition to manage weeds. Including aclonifen in the pre-em mix will give barley crops a little more protection to grow away.”

 Proclus acts on the shoots of weeds as they emerge through the soil, combining it with the root action of flufenacet means increased and more consistent control plus a wider broad-leaf weed spectrum compared to straight Liberator.  T.

Watch the rate

The recommended rate for barley is 1 l/ha Proclus + 0.6 Liberator as opposed to 1.4 l/ha Proclus for wheat. “The slightly lower rate of aclonifen in barley means we can’t expect exactly the same levels of weed control as in wheat, but we are still seeing an uplift in control on 5-7% against black-grass and ryegrass in trials so far and look forward to seeing what farmers can do with it in the field.”

Seedbed quality and drilling depth vital

Farmers and agronomists using Proclus in wheat crops often point out that a good quality seedbed ensures good performance. Proclus needs to be evenly distributed across the soil surface to create an unbroken layer of protection. Aim for an even seedbed, without lots of clods, and consolidated for maximum product efficacy.

Drill to 32mm and avoid heavy rain

Consistent crop establishment is key part of effective weed control. Drill to crops at 32mm to keep newly emerging barley out of the herbicide’s zone of activity in the crucial stages just after germination. Apply within 48 hours of drilling to get the best results. Make sure no very heavy rain is forecast in the day or two after application to ensure efficacy and safety.

Manage the risk of resistance

Flufenacet has been the foundation of barley and wheat herbicides for over a decade and is still very effective in most situations. But Bayer and NIAB research has shown indications of resistance in ryegrass and to a lesser extent black-grass.“Flufenacet provides very cost-effective weed control, but we have to look after the active carefully. Loading more flufenacet into barley and wheat programmes is misguided as we could lose efficacy. Adding more modes of action such as aclonifen is the way to go.“Liberator contains diflufenican which already helps protect flufenacet, adding Proclus adds another layer of protection which current research shows is a low resistance risk. Pair this with cultural controls, patch management and so on and you have the starting point for durable weed control.”

Weed Screen Tour

Ella and James give a tour of Bayer's latest grass-weed matrix trial.

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