Welcome to the first edition for this autumn.
Crops are variable with the more forward crops at 8 leaves; others barely passed cotyledon. Broad-leaved weeds are more prevalent than usual especially where metazachlor use was compromised. Phoma is an issue in some crops. The weather is ideal for blackgrass growth.
Soil temperatures (at 30 cms) in the oilseed rape growing areas are around 11°C – 14.5°C, lower than this time in 2014, but too warm for outstanding results to be achieved with Kerb® Flo 500 for blackgrass control.
Data for soil temperatures and moisture-deficits attached. Please note a 30 cms soil temperature reading is less variable than the more commonly used 10 cm reading.
Propyzamide, the active ingredient in Kerb Flo 500, in common with other residual herbicides breaks down quickly in warm soils. If you treat now, it is likely the speed of breakdown will lead to insufficient concentration of propyzamide in the rooting zone of the blackgrass, inevitably leading to poorer levels of control.
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. Both these criteria are rarely met before November.
This advice has been proven in extensive trials over many variable autumns. Similar advice would apply to ASTROKerb.
More Kerb Weather Data will be supplied as the season progresses.
Check out application conditions for your local postcode
Click on the My Farm LifeCycle logo to check out forecast conditions for optimizing Kerb Flo 500 and ASTROKerb applications on farm. Simply enter your postcode in the banner and click GO to view the results.
What size of broad-leaved weeds does ASTROKerb control?
ASTROKerb applied at 1.5 L/ha or 1.7 L/ha will give very good control of small (2-4TL) mayweed, poppy, chickweed, groundsel and pansy.
When applied at 1.7 L/ha, ASTROKerb can give high levels of control of mayweed and poppy (up to 8TL) and chickweed (up to 5 branches). Control of groundsel falls off after the 6TL stage, but is very good earlier.
What can I add to the Kerb programme to improve blackgrass
With high populations of blackgrass the use of programmes to give control is increasingly vital. Adding a “fop or dim” with good blackgrass activity as a sequence or tank-mix in the programme nearly always improves control and is frequently better than carbetamide/propyzamide programmes.
Download Topic Sheet 16 “Advice for Blackgrass Control in Oilseed Rape” for further advice.
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