United Kingdom - Bayer oilseed rape establishment poll confirms much improved oilseed rape position

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.

Over 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 (Figure 1).

Figure 1: OSR Establishment Compared to Last Autumn

Bayer National Winter OSR Establishment Poll 2021

Regional variations were fairly high, 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 report better establishment and more reckon they’ve fared worse than last year. Even here, though, over 40% of growers rate their crop establishment as better and half of these as much better.

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

Dekalb technical specialist, Richard Williams who co-ordinated the study identifies several key reasons for this encouraging position from the data.

“First and foremost, cabbage stem flea beetle pressures at establishment appeared to be far less severe for most this season,” he points out. “Indeed, almost 60% of growers reported little or no challenge from the pest. This compares with just over 40% and less than 20% in the previous two years of our National CSFB Management Study, involving similarly large numbers and broad spreads of growers (Figure 2).

Figure 2: CSFB Pressure at Establishment

Bayer National Winter OSR Establishment Poll 2021 and National CSFB Management Studies 2021 and 2020

“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 adds. “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.”

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 Richard 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 have 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.

The extent to which growers are employing the most popular establishment management techniques – other than earlier drilling and the use of vigorous fast-developing hybrids – identified in the two years of the National CSFB Management Study is also important, Mr Williams feels.

“In particular, over 80% of growers are now actively minimising tillage while just under three quarters are either employing seedbed fertilisation or spreading organic manures,” he notes. “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.

“Encouragingly, after two years of National CSFB Management Study findings underlining their relative lack of effectiveness, almost a third of growers tell us they are now deliberately avoiding using insecticides to encourage predators. And, of those not deliberately avoiding them, lower pest pressures this autumn meant a further third didn’t need to spray at establishment.

“Altogether then, 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,” reasons Mr Williams. “As do scores of 7.2 and 6.9 respectively where crops in both cases came under some pressure from the pest (Figure 3).

Figure 3: Establishment Success by Insecticide Spraying Strategy

Bayer National Winter OSR Establishment Poll 2021

“It may be early days yet for the crop, but given the critical importance of establishment to its success, we are particularly encouraged by this year’s poll findings,” he concludes. “Earlier drilling does bring its own share of spring management challenges. However, the fact that observed CSFB pressures were so much lower than the past two seasons leaves us hopeful that serious larval damage won’t be one of them for most growers.”