Product and agronomy news

What’s happening in fields across East Anglia in October?

Susceptible oilseed rape varieties are nearly at Phoma threshold in Ella Crawford’s area, while grassweed and BYDV control in cereals is also topical this month.

Cereals

Cereal drilling started in the last weeks of September and I would estimate it to be about 50% complete. On the whole, there is plenty of moisture in the ground, so for those with lighter land that have managed to drill and spray pre-emergence herbicides, they should achieve good efficacy. On heavier, black-grass infested land, growers are continuing to delay drilling if conditions allow, in order to spray off further flushes of black-grass prior to drilling.

Liberator (flufenacet + diflufenican) is the key product for the pre-emergence foundation, proving consistent in trials year on year. The top mixing partner is 2L/ha of Defy (prosulfocarb) or pendimethalin, depending on resistance status and Avadex (tri-allate) can also be a useful addition, if applied correctly.

Growers will see the value of later drilling this year, as there’s plenty of moisture around and we’d expect the residual chemistry to work well. With soil temperatures dropping, the chemistry will remain in the top layer of the soil for longer and application within 24-48 hours of drilling will give it the best chance of optimum performance.

With fewer cold, harsh winters in recent years, BYDV is becoming more of a concern. Seed treatments such as Deter will give you up to 10 weeks’ protection against aphid vectors, depending on drilling date and seed rate, and is the main tool against the virus in the early stages of the crops life. Where growers have drilled early, this persistence may reduce to 6-8 weeks protection, so a follow up pyrethroid spray might be needed, but consider carefully whether this is needed. We have seen aphids flying up to Christmas in recent seasons when the weather has remained mild, so monitoring crops and aphid traps are essential.

Sugar beet

As expected, sugar beet yields are generally high, with top sugar contents reaching around 18-19% and promising for growers. There is still some disease around and the later January- and February-lifted crops might benefit from a third fungicide, if not already applied. Be mindful of label restrictions on products such as Escolta (cyproconazole + trifloxystrobin), as you can only use two applications per crop.

Oilseed rape

Oilseed rape crops range from 3-6 true leaves in this area and are past the major flea beetle and slug threats. There have been fewer fields re-drilled this year, which is largely down to people drilling earlier and into moisture. Growers made a start in the first week of August and crops have grown away that bit quicker.

While the showery weather has been favourable for oilseed rape establishment, it means we are starting to see some disease walking through crops this week. Varieties with high resistance to Phoma, such as InVigor hybrids, are seeing low levels of disease, but some more susceptible varieties are nearly at threshold and require a fungicide application soon.

Where crops have reached the 10% of plants infected threshold, treat with 0.32L/ha of Proline (prothioconazole) and follow up 4-6 weeks later to complete the programme against Phoma and cover you for light leaf spot control going into the winter. If the Phoma infection does not reach threshold until after the end of October, it may be possible to apply just one application of Proline, with the increased rate of 0.46L/ha to control both diseases.

The catch of peach-potato aphids, the vector of turnip yellows virus, has increased in suction traps and I have started to find aphids in field crops. Biscaya (thiacloprid) can be applied once in the autumn to reduce virus infection, if aphids are present.

Phoma

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