How to reap rewards from oilseed rape 

• Keep careful eye on all crops

• Good strategy pays dividends

• Return on investment is key

Variable weather last autumn is having a significant impact on the over-winter survival of oilseed rape crops.

There will be no one-size-fits-all approach going into spring, say experts. Instead, crops should be managed on a field-by-field basis – ranging from those which struggled to establish to others which are further forward.

It’s by no means all bad news, though. Overall, cabbage stem flea beetle numbers were lower last autumn, according to the national network of Bayer’s newly launched MagicTrap digital yellow water traps.

But with the oilseed rape crop area for harvest 2025 estimated to be down by 36% on 2024 at around 226,000ha, timely crop assessment and targeted management in the coming weeks could pay dividends this season.

New season oilseed rape crops were generally planted in good conditions across much of East Anglia.

But establishment was compromised by wet weather and a delayed harvest further north.

Strip trial

Bayer trials manager Richard Williams, responsible for Dekalb’s oilseed rape strip trials programme, says: “When I visited our strip trial at Rougham Estate, near Bury St Edmunds in Suffolk in December, it was up to my knees.

“It was drilled on 7 August and that’s what we have to do in the East – we have to get in with the drill early and hit the moisture early.

That’s what the team at Rougham did and they have a fantastic crop.”

It was a similar situation in Herefordshire. Plant counts in the strip trial ranged between 33-48 plants/m² in December – nicely within the optimum range of 30-50 plants/m².

“We know from our trials over several years now that a population of 25-40 plants/m² is needed for the best performance. Some well-established, thick crops are likely to benefit from a little thinning out over winter or, in some cases, a spring PGR.

Key message

A key message is the lack of difference in terms of establishment between DK Excentric, which was launched last year, compared to the tried and tested variety DK Exstar or pipeline variety CWH 596, both of which are earlier varieties.

Bayer technical manager Ellie Borthwick-North urges growers to keep a close eye on crops and manage them on a case-by-case basis. That said, oilseed rape remains the best break crop ahead of a first wheat, she adds.

“As a crop, it will come back into favour – we just need to have some patience and wait for the flea beetle tolerant varieties to come through.

These varieties are starting to appear on the horizon and Ms Bortwick-North says she is getting good feedback from our breeders.

“Right now it’s about getting out and checking crops and making sure we look after them with good farming and good agronomy.”

Top tips for successful spring restart

Cabbage stem flea beetle pressure was lower last autumn than in previous seasons – but growers should still check crops regularly for larvae.

Wet seedbeds in some areas have put crops under pressure from the outset. A realistic appraisal of the likely return on investment should be undertaken by assessing plant populations, rooting and the presence of flea beetle larvae.

January frosts have reduced the canopy size in bigger crops. That said, crops may benefit from an early application of tebuconazole where larger canopies persist.

Growers should consider delaying or reducing the first nitrogen split in well-established, forward crops but prioritise nitrogen on smaller, backward crops.

Light leaf spot symptoms are starting to appear. There is no treatment threshold – growers should apply a fungicide such as Aviator Xpro (bixafen+prothioconazole) at the first signs of disease or as soon as field conditions allow.