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 2 months ago
June
At the end of May oilseed rape crops are in varying stages of flowering, with most coming to the end of their flowering period, depending on location.
The focus for June will be the build up to seed maturity and judging when to apply glyphosate to desiccate the crop.
Spraying at the right time is vital for effective pre-harvest desiccation. Spraying too early will result in loss of yield but spraying too late increases the risk of pod shatter.
Dekalb varieties, and some other hybrids, have in-build pod shatter resistance which prevents some seed shedding in wind and hail and offers a degree of flexibility in the timing of desiccation sprays.
To judge seed maturity, get into the crop and walk fields to take samples. Don’t just sample from the edges of the field, since there is considerable variability within fields and between fields, especially where earlier pigeon attack hindered canopy development. Ideally, sample 20 pods from areas of the crop that hold the majority of the yield.
During sampling, look for seed colour change. When the majority of seeds have changed from green to brown, seed maturity is around 30% and ready for spraying.
When spraying, pay attention to spray quality for optimum coverage and canopy penetration. Using water volumes of 200 – 250 L/ha will help in thicker crops. Then benefit of low-drift formulations of glyphosate, such as products in the Roundup range will also aid coverage of the crop.
Spraying earlier in the day when the relative humidity is higher will help the spray to better penetrate the crop. Where spray timing isn’t optimal, Roundup is formulated to work better than generic glyphosate formulations in hot and dry weather, and is also rainfast in one hour.
A pre-harvest glyphosate application will also remove any remaining weed populations, particularly difficult to control grass-weeds, before harvest.
After spraying, it’s important to be patient and wait for pods and stems to be fully fit for combining., Usually this is a minimum of two to three weeks, depending on the weather.
May
May sees the continuation of flowering and pod development, though where crops suffered heavy pigeon damage over winter there may be significant variation between and within fields. If May weather remains relatively dry and war, the flowering period will be extended.
May usually marks the mid-flowering period and crops will usually have received a fungicide spray to protect against Sclerotinia, however the extended dry period in April and early May means that the disease risk has been low and fungicide applications may have been delayed. If the weather turns wet, the risk of Sclerotinia infection will increase rapidly
It’s important to apply a fungicide in good time as they only provide protectant activity, and with high forward prices, it is worth protecting yield. AHDB’s Sclerotinia infection risk alerts can be used to support decisions on fungicide timings.
The recent warm weather will also have increased the development of any light leaf spot infection on the leaf canopy and the stems. Any wet weather will help to spread the disease through rain splash and infect developing pods.
When planning a fungicide application for Sclerotinia, it’s worth ensuring that it also provides protection against light leaf spot. 0.75 L/ha of AviatorXpro protects against both diseases and offers good resistance management with two actives.
Most fungicides will provide around three weeks’ protection from Sclerotinia and light leaf spot. If the flowering period is prolonged, and depending on when the first Sclerotinia spray was applied, growers may need to consider a second application to prolong protection until the end of flowering and protect yields.
If only one application of AviatorXpro or another SDHI has been made to the crop, another application can be made. Otherwise, Proline is a good alternative up to the maximum total dose per crop.
Priorities now:
April
Warm weather towards the end of March means that most oilseed rape crops are now moving rapidly through growth stages, from stem extension to green bud and flowering.
At green to yellow bud stage the focus will be on pollen beetle. Growers should monitor beetle numbers against thresholds and spray only if these are reached, to prevent significant bud damage and yield loss. However, once the crop starts to flower, pollen beetles become beneficial pollinators and should not be treated.
If an insecticide is required, it should be noted that there is widespread resistance to pyrethroids in pollen beetles. Other insecticide options are available and should be considered.
Many crops may already have received a spring fungicide spray for Light leaf spot, but stem extension onwards is a key time for disease spread through rain splash, so growers should monitor for and spray at the first sign of infection. Proline is an ideal choice for this time of year.
As soon as crops come into flower, the risk of Sclerotinia needs to be considered. A fungicide application, early-mid flowering, before significant petal fall is advisable and AHDB has started to provide weather-based Sclerotinia infection risk alerts to support decisions on fungicide timings.
A three-quarter dose of most fungicides will offer protection against Sclerotinia for up to three weeks. AviatorXprooffers excellent disease control of Sclerotinia and Light leaf spot, with two active ingredients supporting good resistance management and useful physiological effects. In recent Bayer trials and in the absence of disease, Aviator showed an increase in yield.
Priorities now:
March
In general, oilseed rape crops are looking good coming into the first month of spring, and as the daylight hours and temperatures start to increase during the month we will see rapid growth and stem extension.
Monitoring for light leaf spot should be a priority. This is a key time of year for infection and the disease can move rapidly up the plant through rain splash. Growers should pay particular attention to crops if no autumn fungicide was applied, and on varieties with resistance scores of six or below.
The early stages of light leaf spot are difficult to identify and can be sporadic across a field. Light leaf spot may be present in the leaves even if symptoms – which look like small grains of sugar on either side of the leaf – are not yet present.
Using Bayer’s SpotCheck service can help to identify latent disease in the leaves, and where signs on the leaves are unclear. Identifying the first sign of disease is important singe fungicides only provide protectant activity.
In February, SpotCheck results showed light leaf spot was present in 78% of the 83 samples assessed. Signs of the disease were seen in all variety ratings, 4, 5, 6, 7 and 8, but with higher percentage incidence in lower rated varieties.
Choose a robust fungicide that specifically targets light leaf spot. If AviatorXpro or another SHDI fungicide was used in the autumn, a straight prothioconazole such as Proline provides good protection. Tebuconazole can also be a useful fungicide at this time of year, especially if some growth regulation of the crop is required, and can be applied alongside Proline in tank mix.
If a SHDI has not already been used in the crop, AviatorXpro provides a robust alternative with two actives for enhanced control of light leaf spot, along with other physiological benefits.
Whichever fungicide is chosen, spray operators should ensure they use sufficient water volume to achieve good coverage and penetrate a fast-growing canopy.
Priorities now:
February
In general, oilseed rape crops are looking good coming out of winter, with the usual purpling and yellowing in fields where older leaves have died back. However, pigeons are causing havoc for some fields.
Some cabbage stem flea beetle larva caused damage earlier on in winter. The next few months will demonstrate how crops have fared, however, damage this season is far less than in previous years.
The priorities in February are monitoring for light leaf spot, particularly if no autumn fungicide was applied. Growers should focus on varieties with resistance scores of six or below.
Some crops have developed large canopies and there are a lot of clean-looking crops around. However, the early stages of light leaf spot are difficult to identify and can be sporadic across a field. Light leaf spot may be present in the leaves even if symptoms – which look like small grains of sugar on either side of the leaf – are not yet present.
Ideal conditions for disease include wet weather with rising temperatures, so early spring may see an increase in disease incidence in crops. Using Bayer’s SpotCheck service can help to identify latent disease in the leaves, and where signs on the leaves are unclear. Identifying the first sign of disease is important singe fungicides only provide protectant activity.
Autumn fungicide applications will have run out of steam by now, so in all crops, where disease is identified, a fungicide application is advised.
If AviatorXpro or another SHDI fungicide was used in the autumn, a straight prothioconazole such as Proline provides good protection. Otherwise, AviatorXpro provides a robust alternative with two actives for enhanced control of light leaf spot, along with other physiological benefits.
Club root has been observed in some fields, so growers should take note of any stunting symptoms above ground and look for signs of clubbing on the roots. Monitoring and recording club root incidence can help in the planning of future rotations.
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