Vigour is priority for oilseed rape
- Establish crops early for best results
- Manage with nutrient and regulators
- Consider yield, gross output and disease
Selecting oilseed rape varieties that establish quickly and outgrow pest and disease threats should be a priority this year, farmers are being told.
From cabbage stem flea beetle in hotspot areas to slugs and pigeons almost anywhere, oilseed rape often faces a tough start. It is a challenge made harder with the loss of neonicotinoid seed treatments – so getting crops drilled and away quickly is vital.
Sowing vigorous varieties early can trigger worries about thick, forward canopies that can lodge later. But Hutchinsons national seeds manager David Bouch says it is better to be in this situation and manage it with nutrition and growth regulators than have poorly established crops.
Semi-dwarf varieties, such as DK secret, could help mitigate these corners in early drilling slots, says Mr Bouch. They benefit from the strong autumn vigour of hybrids, but produce shorter, stiffer canopies less prone to lodging. Semi-dwarfs can also mean quicker harvesting.
With unpredictable disease pressures – notably phoma and light leaf spot, Mr Bouch urges growers to select a mixed portfolio of varieties with different agronomics to spread risk and potentially ease crop management through the season.
“Light leaf spot has traditionally been the priority in the north, but we’ve seen it in the south of the UK too. So much depends on the season. In some years phoma is a bigger concern, so it pays to mitigate against this risk uncertainty by growing a range of varieties.”
Yield, gross output and disease scores remain key factors when assessing varieties. But Mr Bouch says growers should also carefully consider autumn and spring vigour, drilling date, maturity and resistance to pests or diseases.
Erucic acid levels
The increasing popularity of herbicide-tolerant Clearfield varieties could see more growers include them in cropping plans especially if European policy makers proceed with proposals to tighten limits for erucic acid levels in oils and fats destined for the food industry.
This would see the current erucic acid limit in “00” varieties cut from 5% to 2% and has prompted concerns that more growers may be penalised or have loads rejected. “The benefit to the final price you receive can far out weigh any yield penalty associated with growing a CL variety.”
Major sources of erucic acid contamination are thought to include volunteer High Erucic Acid Rape (HEAR) and weeds such as charlock, wild radish, and mustard. Better control of these issues using the Clearfield system could have important benefits for growers suppling food markets.