Welcome to the second edition for this autumn, providing timing guidance for propyzamide applications to oilseed rape.
Soil temperatures (at 30 cms) are becoming cooler, close to 10°C, in northern and central areas. In eastern areas soil temperatures remain too warm (11°C – 12°C) for effective Kerb® Flo 500 and AstroKerb applications. Broadly with temperatures set to stay mild we would expect to see a lot of applications start in around about a week’s time. .
It is important to wait until soil temperatures have cooled to less than 10°C as this optimises the blackgrass control activity from your propyzamide application. Cooler soil temperatures slows propyzamide breakdown and ensures blackgrass roots are exposed to propyzamide for longer periods of time, thus optimizing control.
With recommendations and applications already being made and with rain forecast for parts of the UK for the weekend it is important to remember that there is an increased risk to water if there is heavy rainfall within 48 hours of application to a dry soil, so caution is recommended.
Use the maps and links below to find the data for soil temperatures and moisture-deficits in your region. Please note at 30 cms soil temperature reading is less variable than the more commonly used 10 cm reading.
Whilst overall conditions across the UK may not be currently suitable for Kerb (or ASTROKerb) applications, please check your local status using the postcode checker for a more accurate reading.
For optimal blackgrass control Corteva Agriscience recommend Kerb Flo 500 and ASTROKerb® applications are made when soil temperatures are 10°C and falling, and there is sufficient soil moisture in the soil for grassweed uptake. Both these criteria are usually met from the first week in November.
More Kerb Weather Data will be supplied as the season progresses.
Check out application conditions for your local postcode
Simply enter your postcode in the banner and click GO to view the results.
Should I apply ASTROKerb earlier?
As ASTROKerb will mainly be used for blackgrass, this should drive application timing. ASTROKerb has both contact and root activity on poppies and mayweeds and in our extensive trials programme, when optimally timed for blackgrass control even where canopies were large, control of these broad-leaved weeds has been good. Where broad-leaved weeds are the sole driver an earlier application could be considered before broad-leaved weeds become too large.
Can I apply Kerb Flo 500 in a frost?
Kerb Flo 500 may be applied in frosty conditions but avoid application onto frozen ground where subsequent rainfall could result in run-off into watercourses.
For ASTROKerb please ensure frost is off the target broad-leaved weed.
Download Topic Sheet 16 “Advice for Blackgrass Control in Oilseed Rape” for further advice.