Reset fields hit by resistant ryegrass

Cultural controls are helping to rid fields of herbicide resistant ryegrass on a Nottinghamshire farm.

It comes after father and son team Peter and Rob Barlow took on 160ha of land infested with the weed. Soil types vary from gravel through to heavy loam across the farm which encompasses 260ha rented from the Crown’s Bingham Estate.

“Back in 2019 a neighbour was retiring and we thought we’d like the opportunity to take on his block of land,” explains Rob.

“From looking and talking over the hedge, we knew there was an issue. A traditional approach to farming, combined with a history of baling contractors, had enabled ryegrass to get a firm hold and spread prolifically.”

Weed control

Progress has been made combatting ryegrass with two years of careful management. But a couple of stubborn fields remain. Spring cropping isn’t an option, so the duo use a combination of Westwold grass and maize to get the same benefits. 

“After harvest, we drill the grass, and graze it over winter,“ says Rob. “In the spring, a cut of silage is taken before it is sprayed off and the maize crop is sown.  It’s working well and controlling the ryegrass.”

Where fields haven’t been ploughed for 5 or 6 years they’ve been able bury the seed and apply Luximo.

“That’s had great results and really brought the ryegrass back under control.”

Delaying drilling is another tool being deployed across the acreage, although Rob admits there’s often a conflict between getting a crop established and optimising weed control.  “Clean land is drilled first, usually at the very end of September.”

To reduce the risk of seed spreading, field are sprayed and combined in the same meticulous order. “All machinery is blown off and washed down to reduce the risk,” says Rob. “We go into the cleanest blocks first and do the dirty ones last.”

Spray programme

On the home farm, the herbicide programme has historically been Liberator (flufenacet and diflufenican) plus Stomp Aqua (pendimethalin) at pre-emergence followed by Axial Pro (pinoxaden) at post emergence, and it’s worked well.

But Rob says there were too many survivors on the new fields. “Our agronomist, Graham Partington, took samples and sent them off for testing. We weren’t surprised when the results confirmed resistance to herbicides.”

It was one reason Rob and Peter accepted a suggestion by BASF agronomy manager Colin Mountford-Smith to trial Luximo on their worst remaining field. With such a difficult and high population of ryegrass, it was an opportunity to test Luximo’s performance.

A crop of Typhoon was drilled across the 24ha field on 9 October 2022 and herbicide treatments applied two days later.

The middle of the field received 0.7 litres of Luxinum Plus and 2 litres of Stomp Aqua pre-emergence. The outside of the field land received the ‘farm standard’ of 0.6 litres of Liberator and 2 litres of Stomp Aqua.

Both blocks were followed up with a spring post-em application of 0.8 litres of Axial Pro. There were also three smaller blocks treated with Liberator and pendimethalin; Luxinum Plus and Stomp Aqua; and an untreated block.

Final count

At final count on 25 May, the untreated plot had over 670 ryegrass heads per square metre. Of the treated plots, Luxinum Plus and Stomp Aqua had the greatest efficacy with just 89 heads per square metre.

The farm standard of Liberator + Stomp Aqua followed by Axial Pro resulted in 228 heads per square metre.

“In the autumn, the control from the Luxinum Plus looked to be around 95%,” says Rob. But ryegrass re-appeared in early spring as a second flush ocurred across the UK as a very wet March prompted a wave of late germination.

While an extremely useful case study for Rob and his father, the field will now be put into a  grass ley.

“Ryegrass is such a massive plant that only the most serious chemistry will touch it. We can’t afford to risk it spreading to other areas of the farm,” he says.

Mr Mountford-Smith says: “That is why chemistry is the ‘backstop’ and all cultural controls are still critical.”

Where the ryegrass population isn’t as high as the trial field, Rob intends to continue with the cultural controls already in play. 

The herbicide programme, however, will undergo significant change.We’ll be using a lot more Luximo,” he says.

“We’ve got a question mark over the Axial Pro but we will to wait for the resistance results before dropping it.  If there is resistance, it’s a lot of money to spend. As we’ve not used Avadex before, we have options.”