We know that growing oilseed rape can be challenging so we have gathered together everything you need to know about oilseed rape here. From establishment to harvest we can provide insight about crop management and protection to help maximise yields.
Posted 10 months ago
July
As harvest gets underway, take care to assess the level of maturity across the field. Patchy and poor establishment, damage from cabbage stem flea beetle (CSFB) and pigeons, and lack of soil moisture means that some crops are very variable.
Pod samples should be representative of the field, taken from a range of plants and not just from the headland and tramlines. Once the majority of seeds in each pod have tuned from green to brown, a desiccant spray can be applied if necessary. Remember that cooler weather can delay senescence.
July is also a good time to make finalise your varieties for next season.
When making your choice, consider your main priorities: yield, fast establishment, spring growth, disease resistance, weed control, or specialist markets.
Hybrid varieties, such as those from DEKALB offer a range of benefits to suit most situations, and all include pod shatter resistance to assist with harvest timing flexibility.
In areas with high CSFB pressure, fast-establishing varieties can help the crop grow away in the autumn. Similarly, varieties with strong spring re-growth and tolerance to the larvae can help to protect yield potential.
In the west and north, or where CSFB is a lesser concern, you may want to focus more on varieties with good disease ratings. All DEKALB hybrid varieties have double phoma resistance, which reduces the risk of phoma stem canker. If light leaf spot is a concern, look for varieties with a resistance rating of 7 or higher.
Turnip yellows virus is an increasing concern, particularly with the loss of key active ingredients to control aphids in the autumn, so look for varieties with TuYV resistance.
Clearfield varieties are beneficial where broad leaved weeds are hard to control, particularly charlock, or when growing a companion crop like mustard to deter CSFB.
And finally, those looking for alternative markets for oilseed rape should look to HOLL varieties, which can offer substantial premiums and oil bonuses.
Priorities now:
June
June can be a quieter time: the key work is accurately assessing seed maturity and deciding when to spray pre-harvest glyphosate towards the end of the month, if you are desiccating.
As always, it’s a tricky balance: spray too early and reductions in yield can be as much as 1-2% with each day of seed filling lost, but the wait does potentially increase the risk of pod-shatter. Farmers can at least take comfort that all Dekalb varieties have inbuilt pod-shatter resistance, reducing the risk of seed shedding, allowing greater flexibility with spray timing.
Judging maturity means more walking: Crop maturity and therefore timing of desiccation may vary a lot between farms as well as within individual fields. Of course, a lot of oilseed rape crops have suffered this year at the hands of pigeons and cabbage stem flea beetle, so it’s important to take a representative sample of pods from wherever the majority of yield is being held within the canopy. Take a sample of 20 pods and as a rule of thumb, if the majority of the seeds per pods have changed from green to brown, the crop has reached the earliest correct stage for spraying and seed moisture of 30%.
Consider spray quality, for optimum coverage and penetration we recommend using 200-250L water in thicker crops and using low drift nozzle or formulations if possible. We also suggest spraying earlier in the day during hot weather periods, when relative humidity is highest. The current hot dry spell does favour modern Roundup products which perform well in these conditions, show minimal drift and are rainfast if the weather does change.
Of course, OSR easily hides a lot of grass weeds which could be more of an issue in the following crop – so another significant benefit of desiccation at this time is dealing with any substantial weed populations.
Once glyphosate has been sprayed farmers need to be patient and wait for the pods and stems to be fully fit for combining which could take up to three weeks or more.
Priorities for this month:
May
Majority of crops have reached mid flowering, and the rain forecast for early May will be gladly received. However the accompanying warmer temperatures will increase the risk of Sclerotinia, so any outstanding first sprays (of products such as Proline or the newly-available Aviator (bixafen + prothioconazole)) need to happen as soon as possible, if the risk remains high. A follow up spray may be required if the flowering period continues past 3 weeks from the first spray. Monitor crops and utilise forecasting systems to aid fungicide decisions.
Light leaf spot (LLS) can still pose a threat and thriving in warm, moist conditions means it will keep cycling through crops and may move up the canopy. Any Aviator or Proline applied against Sclerotinia will also help reduce LLS.
Seed weevils may be present in places, creating entry points for pod midge. Best-practice monitoring is needed to measure weevil incidence and treat them as soon as levels reach threshold, but the rain may help keep their incidence down.
Weather patterns earlier in the season mean a huge range of growth stages right now across the country (often within one field) so pest-management investment will have to be decided on a field-by-field basis. Given that oilseed rape is one of the only paying crops this season, protecting its yield remains critical.
Priorities this month:
April
Warmer, drier weather is, at last, helping surviving oilseed rape crops grow away from flea beetle and waterlogging. As they move rapidly towards and into flowering, it is particularly important to watch out for Sclerotinia and maintain light leaf spot protection, especially following the epidemic levels of disease identified by Bayer’s SpotCheck this season.
The Sclerotinia risk is likely to vary very widely from field to field with more-forward crops starting to flower while those struggling to recover are well behind and seem certain to flower over a much longer period.
Extended flowering, of course, means a greater exposure to Sclerotinia, so a repeat flowering spray may be necessary to see these crops through their vulnerable stage.
Extra protection to reduce light leaf spot cycling and build-up should pay particular dividends in many cases too.
With its proven activity against both Sclerotinia and light leaf spot, the newly-available chemistry of Aviator (bixafen + prothioconazole) will be especially valuable here. As an SDHI, bixafen’s well-recognised physiological value in maintaining green leaf area offers additional help to backward crops.
While a pollen beetle spray hasn’t been necessary for most forward crops, those flowering later and coming into the green/yellow bud stage may need protecting with a timely insecticide spray. And no-one should forget how damaging seed weevil – and ensuing pod midge infestations – can be.
Priority this month (location dependent):
March
Surviving oilseed rape crops will start to grow away in March, but cabbage stem flea beetle larvae may well still threaten and will need monitoring. It is worth making observations about which varieties and establishment regimes have coped best with both initial attacks in the autumn and any larval damage to help inform decision making next autumn.
Given the difficult weather conditions over autumn and winter, travelling has been a challenge and there are many crops which have not received a fungicide spray to date. The mild temperatures have been conducive to light leaf spot development, and so utilising a fungicide such as Proline (prothioconazole) at this timing is critical to protect the crop ahead of stem extension.
This is particularly pertinent given the difficulties drilling winter wheat – it may be that oilseed rape is one of the only paying crops this season, and so protecting its yield could be critical come harvest.
Priorities this month (location dependent):
Find out more information on the key disease threats to your oilseed rape crop. For each disease you will find out the importance of the disease in terms of potential yield penalty, how to identify the disease in its early stages and our advice on the best control strategies.
