Propyzamide is a selective, systemic herbicide for use in oilseed rape. It controls key grass weeds such as blackgrass and ryegrass which are resistant to alternative chemistry.
There is no known resistance in Europe to propyzamide which makes it a key tool to help manage and reduce the burden of these weeds across the rotation.
Renowned herbicides such as Astrokerb® and Kerb® Flo 500 contain propyzamide and are the cornerstones of many herbicide programmes.
Propyzamide (Pronamide) is the common name for: 3,5-Dichloro-N-(1,1-dimethyl-2-propynyl) benzamide.
It is a member of the amide or substituted amide chemical family (sometimes referred to as benzamide family of chemistry).
Propyzamide acts by preventing plant cell division. It inhibits mitosis by binding to tubulin and preventing its assembly into microtubules.
It has herbicide Mode of Action Classification - Group 3.
Primarily root uptake and upward translocation.
Propyzamide must move into the soil root zone for effective contact with plant roots.
Propyzamide is primarily translocated upwards in plants following root absorption.
By forming a chemical layer in the upper soil zone, propyzamide affects plants through root absorption (direct contact at germination and/or emergence).
Because of the length of soil persistence, soil activity may last up to three months.
In frosty conditions and in response to frost heave, plants such as blackgrass may produce adventitious roots.
These rootlets absorb propyzamide from the surface layers of soil. Under these conditions, despite plants being well established and deeply rooted, excellent control can be achieved.
Grass weeds: Blackgrass, ryegrass, annual meadow-grass, barren brome, volunteer cereals, wild oats.
Broad leaved weeds: Common chickweed, black bindweed, black nightshade, fat-hen, redshank, small nettle, speedwell, forget-me-not, knotgrass.
It is important to get a good residual layer for robust control. It’s a balance – the conditions need to be right – but if you wait too long and the blackgrass plants are too big it can give poorer results.
Use Kerb Weather Data to keep track of the best time to apply. Sign up to our Kerb Weather Data e-newsletter and receive autumn application advice on soil temperatures to support optimum timing of Kerb & Astrokerb.
Assess black grass population and select appropriate dose rate.
750g ai/ha good control.
840g ai/ha gives more robust control especially in heavy blackgrass populations.
Apply when soil temperatures are declining and there is sufficient moisture.
Optimum temperature is 10ºC and declining at 30 cm of soil
Adequate soil moisture is essential to move the chemical into the root zone of weeds
Trials have shown the best time to apply tends to be end Oct-November because this is the time where soil temperatures are falling and are ideal for propyzamide application.
Trials looked at timings, rates and soil temperatures for the most effective control of blackgrass with propyzamide.
The Kerb Weather Data (KWD) tool is meant to be used as a guide to local weather conditions. It can aid growers and advisors in making local tactical decisions to optimise their Astrokerb® and Kerb® Flo 500 applications and thus their activity against blackgrass. It is based on the traffic light system to help farmers optimise their application timings.
For Kerb Weather Data with advanced functionality, download the free Corteva Arable App.
Affected weeds that have emerged will slow or stop growth and initially look stunted, followed by chlorosis and necrosis.
Typical symptom in grass weeds is swelling of the meristem at the stem base, caused by cell growth continuing but cell division being stopped.
Other symptoms of affected plants include a dull appearance, sometimes with reddening.
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.
Go to our propyzamide stewardship page to read more about guidelines and practices to follow.
If you would like to contact a member of the team, click here to find your local area manager.
Alternatively, you can call our Technical Hotline on 0800 689 8899, email ukhotline@corteva.com, or complete our enquiry form.