Kerb Weather Data – Report 4 – week ending 11th November

Kerb® Weather Data gives timing advice for application of Kerb Flo 500 and ASTROKerb® to oilseed rape. (For beans, Kerb Flo 500 must be applied within 7 days of drilling but before crop emergence).

With falling temperatures and recent rain/snow, consider application to oilseed rape when conditions allow. The decision to spray now or wait should be based on local conditions, including the realistic chances of being able to travel and consideration of potential risk to watercourses. Consult VI for advice on protecting water-courses.

Use the links below to find the data for soil temperatures and moisture-deficits in your region.  Please note a 30 cms soil temperature reading is less variable than the more commonly used 10 cm reading.

For optimal blackgrass control Dow AgroSciences recommend Kerb Flo 500 and ASTROKerb applications are made when soil temperatures have got down to 10°C and falling, and there is sufficient soil moisture in the soil for grassweed uptake.

More Kerb Weather Data will be supplied as the season progresses.


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Do I need a dry-leaf for application?
The propyzamide active in Kerb Flo 500 is soil-acting so spraying wet weeds at run-off or light rainfall after application is not an issue. Ideally, the rainfastness of ASTROKerb is 1 hour for the aminopyralid element. Spraying on a drying leaf is OK but if rainfall falls within 1 hour and causes run-off efficacy may be reduced. All applications should be made with due regard to water stewardship, i.e. do not spray where there is a risk of run-off to adjacent watercourses.

 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.

 If severe frosts are experienced before Kerb application, there may be some shear of surface roots of blackgrass. In this situation adventitious roots may subsequently develop, which will take up propyzamide from a later application. In this scenario we have seen excellent results from December/January application.

 Download Topic Sheet 16 “Advice for Blackgrass Control in Oilseed Rape” for further advice.