Ryegrass resistance is increasing. Our research into ryegrass across the UK has helped UK farmers to find ways to maximise every percentage point of ryegrass control. Understanding ryegrass in detail is key to creating your best possible control strategy to help manage this problematic grass weed sustainably and profitably. Cultural controls, competitive cropping and product  choice and application all form key elements of an integrated management strategy.


Ryegrass resistance is becoming more widespread which means it’s more important than ever to sample seed to understand the ryegrass populations on your farm.  Resistance testing requires around a mug of seed (approx. 250 – 300 ml), which should be allowed to dry fully before being bagged to send for testing. Samples submitted to testing labs by the end of July, would normally have results back by the end of September, to aid agronomy decision making.

Did you know?

It only takes 5 ryegrass plants per m2 to cause a 5% yield loss in wheat.

Did you know?

Autumn germinating Italian ryegrass produces 23x more seed than spring germinating. Italian ryegrass can be identified by the fact that it has leaves rolled in the shoot and awned spikelets.

Delayed Drilling

Where grass weeds are a concern, delayed drilling is highly recommended.

Autumn germinating ryegrass can emerge from September through to December.  Delayed drilling allows some of these ryegrass seeds to germinate so they can be sprayed off before drilling the crop. While ryegrass can continue to germinate after the crop has been drilled, delayed drilling increases your percentage of ryegrass control. A pre-emergence herbicide treatment can then tackle any remaining late germinating ryegrass.

Delayed Drilling

Competitive Cropping

If you’re considering barley in your rotation, hybrid barley can be a great option to include in your ryegrass control strategy.  At Doncaster, we’ve found that greater competition gives fewer grass weed tillers.

Hybrid barley is showing consistently higher levels of competition and a lower number of ryegrass tillers than winter wheat or conventional barley. Hybrid barley is also demonstrating a reduced number of weed ears, due to a greater proportion of weed ears remaining below the crop canopy.

Product Choice

DEFY is a key product in a ryegrass situation. Trials data has shown that Defy adds >10% control even where new actives are included, meaning it should form the base of your stack when faced with ryegrass.  Defy is an essential pre-emergence herbicide partner product for both winter and spring cereal crops.  Increasing rates of Defy increases control, regardless of weather conditions. While we know the aim is always to go on with a pre-emergence herbicide, sometimes conditions don’t allow this.  If this happens, you can adapt rates of Defy to suit your peri-emergence and post-emergence programme.

“Ryegrass is certainly now the more prevalent and aggressive grass weed on the farm, compared to black-grass. Alongside cultural controls, the herbicide strategy is entirely dependent on the robust pre-and post-emergence autumn treatments. As part of the pre-em herbicide stack, DEFY offers a good level of control. It’s work in progress, but ryegrass can be managed.”

Ted Holmes, Farm Manager, North Warwickshire


Application is more than getting your chosen product onto the crop.  We research and trial application techniques to give you the best advice on how to do this as sustainably as possible, considering weather conditions and the environment to help you get the most out of every drop.

That’s why we advocate to go low, go slow and get covered.  Boom height, forward speed and water volume can all improve your application practice, especially with a drift reducing nozzle in certain situations.

Application can contribute up to 50% of your chemical control so every little improvement in technology or technique can increase control.

Targeting ryegrass in the spring

Ryegrass that had evaded control of autumn treatments, or has emerged over the winter, may still be controlled in the spring with Axial Pro.

Axial Pro is also highly effective for post-emergence targeting of ryegrass in spring sown crops, including spring barley and spring wheat.

Removing weeds as early as possible in the spring will reduce further impacts of competition, as well as limit seed return later in the season.

Axial Pro can be safely tank-mixed with a range of fungicides and PGRs in the spring. For use in herbicide programmes always adhere to specific sequencing and mixing guidelines.  

Spring application rates can be effectively tailored to target weed size and growing conditions, for optimum results and returns. For ryegrass beyond two-tillers (>GS22) the Axial Pro application rate should be at 0.82 l/ha.

Application technique in the spring should also be tailored to the crop and weed growth, selecting nozzle choice, water volume and operating pressure to optimise target coverage.