The Agriculture and Horticulture Development Board (AHDB) has highlighted the threat of clubroot in crops of oilseed rape (OSR).
This follows the damage caused by the disease in an OSR trial in southern Scotland. Similar problems were encountered during the previous season at a trial in the northeast of England. Significantly, no history of clubroot had been recorded at either site.
According to AHDB agronomists, it is important to look for early signs of clubroot and to manage it accordingly.
Oilseed rape
More generally, the 2021/2022 season has been relatively kind to winter oilseed rape in trials and commercial crops grown in the UK.
For the second year running, there was plenty of moisture around at drilling and flea beetle pressure was relatively low, in many cases.
However, it was not all plain sailing. A small number of trials were lost, following pigeon damage and poor establishment.
Currently, the average gross output value of the control OSR varieties is 5.72t/ha, almost 0.5t/ha above the four-year average value (5.23t/ha), according to the AHDB.
AHDB Recommended List (RL) yields are reported as a gross output, which is the seed yield adjusted for oil content.
Values are represented as a percentage of the control varieties: Three conventional varieties (Campus, Aspire and Aurelia) and two hybrid varieties (DK Expansion and Temptation).
Yields
With the latest trial results considered, the 2022 gross output value of the control varieties (5.72t/ha) has increased further over the four-year average (5.23t/ha).
The strong yields are partly due to good autumn establishment conditions and the relative absence of flea beetle damage compared with some recent years.
In the current data for 2022, the highest-yielding recommended varieties are three UK hybrid varieties: LG Aviron; newly recommended LG Auckland; and Aurelia (all on 105%).
UK recommended hybrid variety Ambassador is close behind (104%). Newly recommended Annika is the leading conventional variety on yield (102%), followed by Acacia (101%).
In 2022, Crocodile, with a specific recommendation for growing on land with common strains of clubroot, continues to do well (103%).
On 98%, newly recommended Matrix CL is the highest yielding of the herbicide-tolerant varieties, with LG Constructor CL on 95%.
So far, based on the four-year average values, the highest-yielding recommended varieties are newly recommended LG Auckland, Ambassador and LG Aviron (105%), with Aurelia, LG Adonis and newly recommended PT303 on 104%.
The highest-yielding conventional varieties are Acacia and newly recommended Annika (both on 101%).
Crocodile is the highest-yielding clubroot-resistant variety (100%) with UK herbicide-tolerant variety, Crome, on 97%.
Of the herbicide-tolerant varieties, the UK variety Matrix CL is the highest yielding (98%), followed by the UK variety LG Constructor CL (95%), UK variety DK Imprint CL (92%) and the East/West variety PT279CL (91%).
