The national oilseed rape acreage has not returned to its levels prior to the withdrawal of neonicotinoid treatments for flea beetle control, but it is still the main break option for the North of England and plant breeders are continuing to make progress, according to AHDB Recommended List (RL) manager, Paul Gosling.

Several new oilseed rape varieties, including some with recommendations for the North of England, have made it to the latest Recommended List (RL), says Mr Gosling.

“Turing from LSPB is a high-yielding variety, producing a gross output of 107 per cent, coupled with a score of seven for light leaf spot resistance,” he said. “However, it does not have turnip yellows resistance and the same applies to pod shatter resistance. Attica from LG Seeds matches Turing’s yield figure, but it has turnip yellows resistance and pod shatter resistance.

“Another new variety is LG Wagner. It is recommended only for the North and in this region it has a gross output yield 108 per cent. It has turnip yellows and pod shatter resistance, along with a solid score for stem canker and light leaf spot. The pod shatter resistance may be of particular interest in northern regions, as it offers some protection for the crop in catchy weather.

“The Clearfield variety Beatrix CL has also been recommended solely for the North. Its herbicide tolerance will be useful for the control of volunteers and other brassicas, but its northern yield of only 94 per cent means it may only suit specific situations.”

Paul Gosling, AHDB Recommended List manager

Paul Gosling, AHDB Recommended List manager

Mr Gosling picked out another couple of new oilseed rape varieties that could suit northern farms.

“Frontier’s Tom is five points lower on yield compared with Turing and Attica, but it is the equal highest-yielding conventional variety in the North, with a score of 7 for light leaf spot and 6 for stem canker. On the down side it does not have pod shatter or turnip yellows resistance; conventional variety breeding progress has tended to lag behind.”

Among the ‘tried and tested’ varieties, Mr Gosling selected Ambassador and Amarone from LG Seeds and Aurelia, from United Oilseeds. This trio had a history of good northern performance, with high yields and favourable resistance scores for the main diseases.

“Ambassador has a gross output score of 103 per cent for the North and scores a 9 for stem stiffness,” he said. “It also has pod shatter and turnip yellows resistance. Amarone is a conventional variety scoring 102 per cent for yield in the region. It has a relatively short canopy and a light leaf spot resistance of 7.

“Aurelia has proved to be a good all-rounder, with gene-specific pod shatter resistance and resistance to turnip yellows virus. It scores an 8 for lodging resistance and an 8 for stem stiffness, along with a 7 for light leaf spot and a 6 for stem canker.”

In terms of cabbage stem flea beetle control following the ban on neonicotinoid treatments, Mr Gosling pointed to two main options for management control.

Oilseed rape is still the main break option in the North

Oilseed rape is still the main break option in the North

“The most successful approach in our trial plots has been to drill oilseed rape seed early, in order to get the crop established before the main period of migration of the adult flea beetle. However this comes with the accompanying risk that lack of soil moisture will leave the seed dormant for extended periods, potentially increasing the risk of losses. Another negative aspect is that it may lead to large numbers of beetle larvae, creating problems in the spring.

“The alternative is late sowing with the aim of waiting until the end of the beetle’s migratory period, but if the weather turns then drilling will have to take place in less-than-ideal conditions. In the worst-case scenario, it may not be possible to get the crop in the ground.”

The first regions to suffer from the neonicotinoid ban were East Anglia and the Home Counties, he commented.

“Problems with cabbage stem flea beetle in our trial plots were fairly rare in our northern areas until the most recent seasons, when there was considerable damage. This could have been a timing issue, with the sowing period favouring the insect’s migration combined with the drought, but the precise reason is unknown. Growers will need to be on high alert during the main risk periods.

“With no recourse to the main insecticide that the industry relied upon, we have to resort to management techniques for control. Several institutions are conducting trials to find out more about how to minimise beetle attack within our oilseed rape crops. Steady progress is being made, but there is still a lot to learn.”

The UK weather has been favourable and flea beetle damage has been lower for the past couple of years, with growers going back to the crop.

“There is no doubt that its management is more challenging without neonicotinoid chemicals, but oilseed rape still offers a very good break option,” said Mr Gosling.