A new knowledge hub to help support propyzamide best practice in oilseed rape has been launched, ready for the key window for applications.

Developed by Corteva Agriscience, the hub offers a suite of new and updated resources which aim to get more from products containing the active, while ensuring stewardship best practice is adhered to.

Wide application window

Products containing propyzamide (Astrokerb, Kerb Flo 500) can be applied to OSR from 1 October until 31 January, providing the crop has at least three leaves. Despite the relatively wide window, Clare Stapley says 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 require it – in the field, controlling weeds. These new materials we’ve 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,” she explains.

Grassweed control

Clare says Astrokerb and Kerb Flo 500 are key to controlling grassweeds, especially blackgrass and ryegrass in OSR, and their importance has grown in the past decade as they retain the ability to take out grassweeds, notably graminicide-resistant blackgrass.

“Propyzamide works best when applied to cold, moist soils, but this must be balanced with protecting water. Soils should be at 80% field capacity (1-2.5cm of moisture), soil temperature at 10oC degrees centigrade and declining, and an appropriate rate should be selected,” comments Clare.

“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 broadleaf weeds. Only use one product containing propyzamide per crop per year.”


The appropriate temperature range for applications often occurs on or after 5 November. Clare advises that growers should 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,” she concludes.

Resources are available at www.corteva.co.uk/propyzamide