Agronomy Update - December 2020

Jonny Oosthuizen - Bartholomews Agronomist

December is a time we look to finalise any remaining pesticide applications and close the gates for winter. Last year there was still plenty of drilling going ahead, but thankfully mother nature has been kinder and most people are all drilled up.

As soil temperatures fall, residual herbicides for grassweeds in oilseed rape should be considered if ground conditions allow. Some of these herbicides can be mixed with fungicide products targeting Phoma and Light Leaf Spot provided the thresholds are met. Pay close attention to the stewardship surrounding these products and the application cut-off dates.

Continue to monitor the aphid populations in cereals using the technology available and apply any outstanding insecticides, if ground conditions allow, in order to reduce the BYDV threat. With the lack of seed dressing and the wet weather making travelling conditions difficult in some places, there is some concern there may be instances of BYDV in the spring.

We are seeing very large populations of grassweeds in places where drilling occurred early. Frustratingly, the black-grass flush was later this year and many growers didn’t want to wait and risk the same scenario as last year so decided to sacrifice the stale seedbed in favour of having the crop in the ground. This was a risk, and in some places, unfortunately, the grassweed burden will put these crops on the backfoot. There are numerous post-emergent options for grassweed control, but application efficiencies will have to be optimized in order to get the best out of them.