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The Future of Agriculture / News & Resources / Propyzamide Knowledge Hub
Article •  13/10/2024

Propyzamide best practice application advice and stewardship information

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Corteva Agriscience has launched a Propyzamide Knowledge Hub for oilseed rape growers which contains the latest information and advice ahead of the key season for applications. 

Among a suite of new and updated resources, a Propyzamide: Back to Basics website and video has been created explaining how to get the best out of products containing the active, while also ensuring stewardship best practice is adhered to. 

Products containing propyzamide – namely Astrokerb® and Kerb® Flo 500 – can be applied to oilseed rape from 1 October until 31 January, providing the crop has at least three leaves. 

But despite the relatively wide window, central to Corteva’s advice to growers is to focus on using the right rate, in the right conditions and at the right time. 

“This is to ensure growers get the best efficacy as well as making sure the product stays where we need it – in the field, controlling weeds,” says Clare Stapley, Corteva’s oilseed rape category marketing manager. 

“These new materials we have created go back to basics on what propyzamide is, how it works, how to apply it to achieve the best outcome, and practical advice on how to use it responsibly.” 

Astrokerb and Kerb Flo 500 are key to controlling grassweeds, especially blackgrass and ryegrass in oilseed rape. 

Their importance in the programme has grown in the past decade as they retain the ability to take out grass weeds, most notably graminicide-resistant blackgrass. 

“Propyzamide works best when applied to cold, moist soils, but this must be balanced with the need to protect water,” Clare explains. 

“Soils should be at 80% field capacity (1-2.5cm of moisture), soil temperature at 10 degrees centigrade and declining, and an appropriate rate should be selected. 

“Only use the maximum rate of 840gai/ha for severe blackgrass situations. A rate of 750gai/ha or 500gai/ha are recommended for less-severe blackgrass or other grasses and broad-leaved weeds. Only use one product containing propyzamide per crop per year.” 

The appropriate temperature range for applications often occurs on or after 5 November, so growers are advised to be ready but resist the temptation to apply outside of the ideal conditions. 

Data demonstrating the correlation between application date, dose rate and blackgrass control reaffirms the importance of waiting for the optimum conditions.  

Key stewardship information is available here, but ahead of application, operators should also follow key advice, such as:
  • Take care when filling and cleaning the sprayer to avoid a point source contamination scenario.
  • Check soils – do not apply propyzamide when soils are cracked, dry or saturated.
  • Check the weather – do not apply propyzamide if heavy rainfall is expected within 48 hours of application. Check Kerb Weather Data to use the traffic light system which indicates when weather conditions are optimum for Astrokerb or Kerb Flo 500 applications (more detail below).
  • Best use of propyzamide: Find out more about the best time to apply with our propyzamide back to basics webpage.
Apply when conditions are right
  • Moisture – soils should be at 80% field capacity (1-2.5cm of moisture).
  • Soil temperature – at 30cm, maximum 10°C and declining.
  • Use the right dose rate – only use the maximum rate of 840gai/ha for severe blackgrass situations. 750gai/ha or 500gai/ha are recommended for less severe blackgrass or other grasses and broad-leaved weeds (see product label for details).  Only use one product containing propyzamide per crop per year.
To help decision making, spray operators, farmers and their advisors are encouraged to download the Corteva Arable App to access Kerb weather data.


The decision support tool has had significant updates to its functionality in recent years. 

  • Access up-to-date application information for your postcode.
  • Pin point your fields to check if conditions are suitable for propyzamide herbicide applications to winter oilseed rape.
  • Mitigate against run off by checking the slope of your field. 
  • An indication of soil type is also built in.
  • Manually add water boundaries to individual fields.
  • Agronomists can also check postcode information for their farmer clients. 
  • Increased functionality compared to the Kerb Weather Data web tool. 

Farmers can also sign up to receive a free digital newsletter from Corteva, called Kerb weather data, with all the latest news and advice on propyzamide applications. 

A new propyzamide quiz will support learning and offers 3 BASIS points and 2 NRoSO points upon completion.  All quiz forms submitted by the end of January 2025, will be entered into a Corteva prize draw.

All the new resources are available at www.corteva.co.uk/propyzamide.

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