Propyzamide stewardship

Sprayer in OSR field

Guidelines and advice

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Oilseed rape is an integral part of the arable rotation, and a profitable break crop in Ireland. 

Renowned herbicides such as Astrokerb® and Kerb® Flo contain propyzamide and are the cornerstones of many herbicide programmes. They are key to controlling grassweeds, especially blackgrass and ryegrass in oilseed rape, and with no known resistance, propyzamide can help manage and reduce the burden of these weeds across the rotation.  
After a heavy rain event there is a risk of propyzamide attached to soil particles getting washed into surface water. Appropriate planning, management and adoption of stewardship practices must be followed to mitigate this risk. 

Oilseed rape growers are urged to consider the actions they can take to protect watercourses. 

Field selection, tramline placement and buffer zones can all play an important role in effective risk mitigation. 


Before drilling

Before drilling and at establishment

1. Aim to grow oilseed rape on low-risk fields:​

  • Those that don’t slope to a watercourse where field slope is less than 5% (1m fall in 20m)​.
  • Are less susceptible to run-off​.
  • Are NOT bordered by a watercourse​.
  • There are NO field drains​.
  • The field has NOT been deep sub-soiled (below plough layer) or mole-drained within the preceding 6 months. 

2. Consider appropriate establishment, direction of working travel, soil type and topography

  • Layout tramlines so that they do not provide a direct route for water to leave the field.

  • Disturb the surface compaction in the tramlines if possible. ​

  • Ideally establish the crop with true minimum tillage working the top 4-6cm only or by direct drilling.​

3. Use buffer zones ​

  • To reduce the risk of run-off (both water and sediment), that may contain pesticides from reaching water courses 

  • Wide buffers are advisable in particularly vulnerable areas. ​

At application

1. Take care when filling and cleaning the sprayer to avoid a point source contamination scenario. ​

2. Check soils

Do NOT apply propyzamide when soils are cracked, dry or saturated. ​

3. Check the weather

Do NOT apply propyzamide if heavy rainfall is expected within 48 hours of application. ​

4. Best use of propyzamide - apply at the correct time and when conditions are right

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

Apply at the right time:

  • From 3 leaf stage of the crop (1st October) up to before 1st February. 

Apply when conditions are right:

1. Moisture – soils should be at 80% field capacity (1-2.5cm of moisture). 

2. Soil temperature – at 30cm, maximum 10°C and declining. 

3. 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. ​

Useful Contacts

Liz Glynn, Corteva National Field Technical Manager

Corteva Technical Hotline

Oilseed Rape woman

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