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iOSR growers put CSFB tools into practice

Agronomy Issues
Harvesting OSR
Uneven maturity of OSR crops at harvest, as a result of the effects of CSFB, could add a further challenge to growers this summer

James Fountain, who farms near Whittlesey in Cambridgeshire, reported that whilst OSR looked good and plenty of pods at harvest, the effects of CSFB damage did have an impact on crop evenness and maturity.  

This season, he has switched from conventional to a hybrid variety, in an initiative to get the crop up and growing away from CSFB and pest damage more consistently, and particularly for spring vigour. For the first time, he is trying a block with cyantraniliprole insecticide seed treatment this autumn.

James Fountain iOSR grower

Hybrid vigour and tailoring spring crop agronomy is looking for faster growth for Cambridgeshire grower, James Fountain


He’s also looking to evaluate different drilling dates, with one block going in after hybrid barley there’s a chance for some of the OSR to be established earlier, conditions permitting. OSR going in later, after wheat, will also have been preceded by potatoes, which has previously benefited from the residual fertility, he added.   

Spring vigour of hybrid varieties, along with spring nutrition timing, could have an impact of plants ability to grow away from CSFB damage, according to Dr Sacha White of ADAS.

Larvae may also be picking up a spring growth response in the plant, to trigger a movement into the stems, he says.

Furthermore, the larvae appear to sense when leaf petioles are starting to senesce, and will move into another part of the plant before the leaves are shed. The use of spring PGRs to adapt crop architecture may also have a role in influencing larvae feeding activity.

James Fountain used PGR in the spring for the first time last year, with the aim to shorten tall crops, but also to help create branching and a bigger leaf area for light utilisation.

“Possibly with a hybrid variety sown earlier, hopefully into good conditions, we might have an opportunity to look at managing a crop in the autumn with PGR effects there too,” he added.    

Last autumn CSFB damage saw Lincolnshire iOSR grower, Andrew Ward, pull up nearly 40% of the farm’s 210 ha of oilseed rape – a decision made easier with good soil conditions enabling a replacement wheat crop to be successfully established in October.

Andrew Ward iOSR grower

Extending the oilseed rape rotation is intended to improve yields in the long-term for iOSR grower, Andrew Ward


However, even having only left strong crops going into the winter, he believes it has still been further hindered by larvae damage, which had impaired flowering and pod fill. The farm’s target six t/ha yield was revised to a realistic 5 t/ha potential, he warned.

Fortunately, having used Toprex across all the fields, there were no issues with lodging, he added. 

Now, Andrew’s decision has been to quickly move OSR out to one year in six in the rotation - from the current one in three or four - that will enable greater focus and attention during the crucial autumn establishment timing.

For the coming season, he has just 28 ha planned into the rotation, which he says should enable planting to coincide with available moisture and incorporating N and P with the drilling.

CSFB pupae in OSR stem

CSFB larvae pupated in oilseed rape stems. Although 2018 populations were exceptionally high, numbers for the coming season will be more dictated by prevailing weather conditions


“I have always advocated holding off drilling until conditions are favourable for the seedlings,” he pointed out. “That’s typically late August to mid-September. Our best crops usually come from later drilling.”

Dr Sacha White highlighted ADAS monitored trials had shown later sowing, with crops emerging after peak CSFB egg laying, tended to result in fewer larvae in petioles and stems.

“Sowing date appears to be hugely influential,” he advised. “There is a huge data set that indicates later sowing will minimise egg laying and resulting larvae numbers."

“But it has to recognise the risks of getting a crop successfully established, along with the workload of farm autumn workloads. A range of sowing dates, along with other integrated measures, could effectively help to spread risks.”  

By complete contrast, further north in Lincolnshire, Oliver Smith has planned a slight increase in OSR area for the 2020 harvest at Stourton Estates.

“While the CSFB risk is growing in our area, currently we seem able to grow the crop without too many issues," he said.

"However, we are reliant on favourable conditions at establishment to allow this to continue."

Oliver Smith iOSR grower

CSFB appeared to have limited effects on the 2018 OSR crop for Lincolnshire grower, Oliver Smith.  The crop had podded well and fairly even, where there weren’t backward patches, he reported.


He added: “if possible, I will drill earlier in august, drilling all hybrids and using sewage sludge prior to sowing, in an effort to get the crop growing quickly.

“Root development in the autumn is critical for yield looking ahead. I have tended to look towards nutrition in the seedbed and foliar to encourage rooting.”

Read more on the tactics to tackle CSFB

Along with details of iOSR farm trials for the crop’s agronomy next season


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