Oilseed rape establishment and weed control advice for Irish growers
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Successful establishment of oilseed rape and achieving good levels of weed control are key components to achieving high yields. It is essential to manage your oilseed rape crop to gain the maximum benefit from the crop including yield.
Effective autumn weed control is an integral part of managing the crop. Oilseed rape is known for being an uncompetitive crop so managing the weed burden early on with an early post-em application really helps to give it the best chance.
Drilling date, sowing method and cultivation type can play a large role in the need for weed control. The timing, depth, method and frequency of cultivations influence the composition and density of the weed population.
If possible and if time always, try and start with a clean seedbed. Target both grassweeds and broad-leaved weeds from the previous crop.
In previous years, drilling in early August has been a strategy being employed on farms in a bid to use the warmer temperatures and moisture to aid rapid establishment. However, with the later season in 2024 this has been less of an option for many.
If conditions are good for oilseed rape establishment, this of course means conditions are also good for weeds to grow. In this situation check which weeds are germinating so you can respond before the weeds get too big.
Belkar®
Belkar adds a level of flexibility to oilseed rape weed control in terms of rate and timing and can be an alternative to a higher risk preventative approach to weed control strategies, allowing the crop to establish first.
This gives growers and agronomists time to assess the visible weed pressure and determine the impact of pests such as slugs.
Belkar gives control of many key competitive weeds including cleavers, cranesbill, poppy, fumitory, shepherd’s purse and mayweed*. See full list of weeds controlled here.
A range of application timings are possible with Belkar from 2-4 leaves. You can apply it as a single dose, sequential applications or a later dose at a higher rate to fit with the crop and situation.
Astrokerb® and Kerb® Flo
Propyzamide containing products such as Astrokerb and Kerb Flo are key for controlling blackgrass and ryegrass in oilseed rape. Propyzamide is a soil active grassweed herbicide designed to stick to soil particles and in soils of less than 10 °C activity can be as long as 3 months.
Propyzamide forms a layer within the top 5cm of soil where it will be absorbed by the roots of germinating grassweeds causing weed death.
For best results, it is recommended that when planning to use herbicides containing propyzamide to consider non inversion/minimal cultivation techniques to avoid mixing grassweed seed deeper than the 5cm propyzamide active zone.
Some further information you might find useful:
- Growers are advised to implement simple steps which will help ensure autumn and winter-applied products don’t reach watercourses. Find out all you need to know on our dedicated propyzamide stewardship knowledge hub.
- Learn more about Belkar herbicide and autumn weed control in our short video below with Clare Stapley, oilseed rape herbicide category marketing manager at Corteva Agriscience. For window of application information and technical details, refer to the Belkar Ireland product page.
*Best control of mayweed
Use a programmed approach with Astrokerb (contains aminopyralid). To read more about a programmed approach to managing problem weeds, download a copy of our topic sheet here.
Corteva is committed to supporting farmers and agronomists to grow oilseed rape successfully.
Our OSR online hub is your go-to resource throughout the season, offering timely updates and invaluable resources. Be sure to visit and bookmark this section of our website to stay informed and supported every step of the way.
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For more info call our Technical hotline: +448006898899 or email: ukhotline@corteva.com