Oilseed rape crops in England, Scotland and Wales are going into the winter much better established this season, boding well for 2022 performance, according to a state-of-the-crop Dekalb poll conducted in October, by Bayer Crop Science.

The on-line study involved 170 growers with more than 15,000 ha of winter OSR plantings well spread across the main arable areas of country, the results of which were shared at the recent CropTec event.

More than 60% of current plantings are reported to be better established than 2020 – over half of these much better – while just 11% are considered to have got off to a worse start.

Regional variations were fairly high, though, with noticeably more northern and western growers seeing better and fewer worse than average year-on-year crop establishment. In contrast, fewer of those in Eastern England and the East Midlands reported better establishment and more reckon they’ve fared worse than last year.

Overall, growers score a hugely encouraging 75% of this season’s crop area as 8 or more for establishment on a 0-10 scale, while just 5% are scored 5 or less.

Dekalb technical specialist, Richard Williams, who co-ordinated the study identified several key reasons: “First and foremost, cabbage stem flea beetle pressures at establishment appeared to be far less severe for most this season.

“Indeed, almost 60% of growers reported little or no challenge from the pest. This compared with just over 40% and less than 20% in the previous two years of our National CSFB Management Study.

“Clearly linked with this was the continued trend to earlier drilling highlighted in our studies. Fully 55% of growers drilled their crops before August 20 this season, for instance, compared to 45% in 2020 and 31% in 2019. At the same time, only 15% of growers planted in September, down from around 30% previously.

“Our further analyses show CSFB pressures increased throughout the main drilling window. Three-quarters of growers sowing on or before the first week of August reported little or no challenge from the pest against 45% of those sowing in the traditional mid-late August drilling window.

“Alongside this our data continue to demonstrate a clear association between establishment success and CSFB pressure,” he added. “Crops suffering intense or substantial pressure from the pest delivered an average score of 5.8 on the 0-10 scale this time around while those seeing little or no pressure averaged 8.3.”

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Greater use of hybrid varieties in earlier sowing for their recognised establishment vigour and early growth rate advantages is another critical success factor, highlighted by Mr Williams. While the main place for hybrids has traditionally been in the later drilling slots, excluding Clearfield, clubroot resistant, HOLL and HEAR types for a fair comparison, the proportion of hybrids and conventional varieties sown on or before August 20 this season was remarkably similar at around 55%.

Despite the lack of any discernible difference in sowing date, or CSFB pressure between the variety types, hybrids again scored slightly higher in their average establishment at 8.0 against 7.6. This was especially the case where there was a noticeable pest challenge.

Also of note were changes in establishment methods. “In particular, more than 80% of growers were now actively minimising tillage while just under three quarters are either employing seedbed fertilisation or spreading organic manures,” he noted. “What’s more, well over half are minimising tillage and using either seedbed fertilisers or organic manures, and nearly 20% are both organic manuring and using seedbed fertiliser.

“Altogether, only 45% of growers used an insecticide at establishment this season, the vast majority of them just the one spray. An average crop establishment score of 7.9 for those deliberately avoiding insecticides compared to 7.7 for those who sprayed adds further weight to the argument that insecticides are generally of little value in combatting CSFB,” said Mr Williams.