Time oilseed rape herbicides sprays using postcodes
Oilseed rape growers can time herbicides by using their postcode to check whether soil temperature and moisture are at the right levels.
Those looking to use Dow AgroSciences’ post-emergence residual weedkillers Kerb and AstroKerb can use this system to be spot-on with their spray timing.
Timely applications are increasing important as the European Union tightens regulations on pesticides and the key active ingredient in Kerb is one of only two not to show any blackgrass resistance.
Growers need to enter their postcodes into Dow’s LifeCycle website and the system, using Met Office data, will indicate if conditions are right for spraying.
The system uses traffic lights, so red means conditions are not right, amber alerts growers to be ready to apply, and green is the signal that it is right to consider an application.
“We hope this will be a useful decision-making tool for growers,” says David Roberts, oilseed rape agronomist at Dow.
For best result, Kerb needs to be applied when soil temperatures are near 10C and falling, meaning the herbicide is slow to break down and longer persistence in the soil is achieved.
Mr Roberts says current temperatures have not got to that level yet, and this is usually achieved from early November onwards.
Active ingredients |
|---|
| Kerb Flo 500 – propyzamide AstroKerb – propyzamide + aminopyralid |
In addition, good levels of soil moisture are needed to help the herbicide distribute evenly in the top layer of soil, and so the soil moisture deficit should not be less than 50mm and falling.
Both Kerb and AstroKerb have the same four-month application window – beginning of October to the end of January – with the latter product giving additional control of mayweed and common poppy.
With poor blackgrass control in most cereal crops last season due largely to the wet autumn and winter, Mr Roberts sees oilseed rape as an effective break crop to deal with this troublesome grassweed.
He says growers can expect in excess of 90% blackgrass control from Kerb if the application conditions are right.
The key active in Kerb, propyzamide, and rival product carbetamide are the only two herbicides not to show any blackgrass resistance.
Careful spray applications are also particularly important to prevent these residual herbicides getting into water courses and so bringing them under further official scrutiny.
Mr Roberts says careful stewardship of residual herbicides in oilseed rape is vital to ensure their long-term availability.
