What to consider before you spray KERB / ASTROKerb this season

OSR in autumn

Growers should be getting ready to apply ASTROKerb (propyzamide and aminopyralid) and Kerb Flo 500 (propyzamide) to winter oilseed rape. Rape crops have been developing rapidly and most are well past the 3 leaf stage. Most advanced crops have 10 leaves. Even when canopies are dense, excellent black-grass control can be achieved with these herbicides.

Kerb Weather Data – Report 5 – week ending 17th November 2017

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

Soil temperatures have cooled (at 30 cms) in the main oilseed rape growing areas and applications are being made. Still dry for best efficacy on blackgrass in places, particularly in Eastern England, and parts of Nottinghamshire and Lincolnshire, but moisture in the top 5 cms, where the propyzamide is active, will help alleviate this.

Kerb Weather Data – Report 4 – week ending 10th November 2017

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

Soil temperatures are cooling (at 30 cms), in the main oilseed rape growing areas and applications are being considered. In East Anglia, soils are still somewhat dry but rain is in the forecast for the weekend.

Kerb Weather Data – Report 3 – Week ending 3rd November 2017

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

Soil temperatures are cooling (at 30 cms) and are now around 10°C – 13°C, in the main oilseed rape growing areas. In Scotland and the North, applications are now being considered but in many areas soils are also very wet making application difficult. Further South, soils are still warm and are also dry – in the East particularly so. There is considerable risk to water if there is heavy rainfall within 48 hours after application to a dry soil, so caution is recommended. Too dry and propyzamide will not bind to the soil leaving it susceptible to leaching away in a high rainfall scenario and washing too deep into the soil past the rooting zone of the blackgrass.

Control of broad-leaved weeds in winter cereals this autumn

Broad-leaved weeds coming through

In simple terms there are two broad-leaved weed scenarios that require attention in fields this autumn:

The ‘Compromised Residual’ – this can occur because of poor seed beds, dry conditions and residual applications made after the broad-leaved weeds have emerged.

The ‘Not Yet Sprayed’ – this is most likely in fields where grassweed pressure is lighter (so less requirement for residual ‘stacking’) and also where farm workload has meant that fields have yet to be sprayed with any herbicide.