Resilient varieties help turn tide against flea beetle

• Traits help growers fight back

• Good overall disease package

• Think differently for success

A new hybrid oilseed rape variety with resilience to cabbage stem flea beetle promises a big step forward in helping growers successfully grow the crop.

LG Avenger is the culmination of almost a decade of work by breeders Limagrain Field Seeds. It is the first to be commercially available in the UK with the LG CSFB Resilience characteristic.

“LG Avenger is the result of our new methods of breeding oilseed rape varieties, which consider all limiting factors for crop development, including the threat from flea beetle,” says Limagrain oilseed rape product manager Florentina Petrescu.

“It is the only variety with LG CSFB Resilience on the 2025/26 AHDB Recommended List, alongside many other valuable characteristics, including high yield, pod shatter resistance, high oil content and a very good disease package.”

LG CSFB Resilience is the latest trait to help improve rape yields, says Limagrain arable technical manager Ron Granger. Other features include TuYV and pod shatter resistance, sclerotinia tolerance and the N-Flex nitrogen efficiency trait.

“Limagrain has been at the forefront of oilseed rape breeding for the past decade,” says Mr Granger. “We remain fully committed to the crop, despite the reduction in the UK area witnessed over that time.”

Challenges around flea beetle control have been a big factor in the declining area of oilseed rape, which has fallen by around 500,000ha from its peak in 2011/12, to about 235,000ha this season.

Defra figures show average yields for England have also fallen over the past decade, from 3.9 to 2.7 t/ha, although in Scotland, where flea beetle is not yet a major issue, yields have risen, reflecting varietal improvements.

Success stories

“There are success stories where growers are trying new things, and going forward, there needs to be a change to the traditional practices to make rape succeed. Variety choice is part of that.”

Mrs Petrescu describes LG CSFB Resilience as “a novel genetic approach that tackles flea beetle at key crop stages, as part of an effective integrated pest management strategy on farm”.

Resilient varieties feature a series of characteristics that make them better adapted to escaping damage during two crucial periods in the autumn and spring, so it is not just about a single genetic trait, she says.

Reducing the severity of flea beetle damage has a direct benefit on final yield, Mrs Petrescu adds. Research by the Agriculture and Hoirticulture Development Board suggests one additional larvae per plant can cost 50-70kg/ha in lost yield.

Feeding damage by adults and larvae has other implications, such as increasing the entry points for disease, uneven flowering and variable pod maturity. Varieties with LG CSFB Resilience also include characteristics like pod shatter resistance, and a strong disease profile to help mitigate these risks, she says.

Independent backing

Flea beetle is a major issue in many other European countries, including France, where CSFB resilience has been a characteristic on the French Recommended List for the past six years.

Independent data from the French equivalent of AHDB (Terres Inovia) puts LG Avenger as one of the highest rated varieties for resilience on this list.

This supports three years of Limagrain Europe assessments, where LG Avenger outperformed the sensitive control variety and came close to
the most resilient control, LG Aviron.

“Oilseed rape ticks so many boxes as a break crop, both in terms of gross margin, inputs, equipment required, workloads, and agronomy. But in order to grow oilseed rape successfully, growers may need to think differently about how they do it.”

IPM key to successful establishment

Resilient varieties are a welcome addition in the battle against cabbage stem flea beetle. But there is no silver bullet and they should be used as a part of an integrated pest management approach.

Adult flea beetles emerge from rape stubbles for up to six months after harvest, peaking in mid-September. Risk is often higher in crops grown close to a previous OSR crop, although work is ongoing to identify how far adult beetles can fly.

Cultivation of the previous oilseed rape stubble straight after harvest has shown to significantly reduce the number of adults emerging from the soil through the autumn, says Limagrain.

Growers should choose varieties with flea beetle resilience and consider regional performance. They should also consider a companion crop – such as buckwheat, berseem clover – to help disguise emerging rape plants from flea beetle.

Good seed-to-soil contact and soil moisture retention are key to rapid establishment. This means drilling by conditions, not calendar date. Seedbeds should be consolidated. Avoid cultivations that may dry the soil out too much before drilling.

Consider all ways to boost establishment, such as placing nutrition close to seed. Weather forecasting is key to determining drilling conditions and flea beetles should be monitored to assess risk.

Keep records of drilling dates, weather conditions, pest numbers and harvest yields. They will be helpful in future years when deciding where and when to grow oilseed rape to best effect.

Likewise, evaluate the effectiveness of management practices. Use insecticides only where necessary once thresholds are met – and recognise that widespread resistance means pyrethroids may have little impact on flea beetle numbers.