Crop growth

Establishment and crop growth have been very good in the vast majority of winter cereal fields, sometimes worryingly good given the level of growth already present. This is most obvious in early sown winter oilseed rape where growth levels have been exceptional, to the point that they give some cause for concern.

Oilseed rape

On the plus side these big crop canopies should require very little nitrogen in early spring to hit the targeted 3.5 GAI canopy. Indeed, they probably need none, which could make these crops relatively cheap to grow and the green harvest price is currently well north of €500/t.

All these very forward crops need growth regulator but many have already received it. Some growers are considering a very light grazing with sheep to take some of the bulk out of the canopy. This needs to be managed carefully as removing too much canopy could damage the crop and/or slow spring regrowth.

Very forward crops also pose a worry. I remember a somewhat similar situation back in the 1980s where some big-canopy forward crops began to flower very early and then it snowed. The weight of the snow lodged the crop, effectively destroying its potential.

Cereals

The growth in winter cereals has been excellent also and it is particularly nice to see crops sown in early to mid-October looking so well at the moment. But it is also somewhat worrying to see the amount of damage in some of these fields caused by crows. They have certainly made establishment very uneven.

I also see patchy establishment in some recently sown fields, probably as a result of heavy rain, causing waterlogging in hollows in the weeks following planting.

Slugs are quite active and must be watched in many fields.

Insecticide

The continuous growth conditions may be helping crops but the high temperatures must also be helping aphid multiplication and spread. So, the risk of BYDV infection remains high for the moment, at least in terms of the risk from aphids. We still do not know if they are carrying virus or not but the levels of yellowing on strong volunteers in stubbles would suggest that the disease is there to be spread.

Most crops have already received one aphicide. Choice of product should depend on the history of product use in a field. If you got poor results from a pyrethroid in the past, opt for one of the newer actives such as sulfoxaflor (Transform). But if you are spraying for a second time you should use an active from a different insecticide family.

If an early sown crop was sprayed close to the end of October that field may need a second aphicide. It will need to be sprayed in very high-risk areas. Even crops that emerge in November may need an aphicide because of the mildness in the weather.

Temperatures dropping now will not stop the spread where infection has already occurred.