Rain has temporarily stopped play, even on the Downs, but there is definitely a feeling of spring in the air. Some fieldwork in the shape of fertiliser applications and spring seed-bed preparation has taken place, with a number of fields now drilled with spring barley. However, the colder soil temperatures still limit opportunities for grassweed control in cereals. Weeds will need to be actively growing before applications of products containing pyroxsulam or combinations of mesosulfuron and iodosulfuron are considered.
The colder temperatures on manganese deficient and disease affected leaves has left many crops looking a bit “ragged”. Some early sown crops are showing high levels of “gouted” tillers. When conditions allow, an early boost of foliar-applied nutrition to aid crop recovery will be prudent and is likely to coincide with T0 fungicide applications.
This year’s warm and wet winter will impact both nutrient and plant growth regulator (PGR) management. Even late drilled crops have been able to produce a greater number of tillers and are much thicker than normal. In effect, they are now at a similar stage to early drilled wheat, compared to what would otherwise be expected in a normal year. Early PGR management will be critical in order to make the most of the large yield potential from this increased tillering.
Although above ground crops look big and lush, rooting is not so developed. High temperatures have led to higher nutrient mineralisation, but wet conditions have not encouraged roots to explore deep in to the soil. It is pleasing to note no-tilled crops have fared particularly well in soils that generally have higher levels of organic matter, better water infiltration rates and are biologically more active when compared to more cultivated land, with plants which are better able to extract sufficient amounts of water and nutrients and later sustain large canopies – and we know that water availability is strongly linked with yield.
Last autumn, cabbage stem flea beetle (CSFB) in oilseed rape generally did not prove an issue during the establishment phase. However, we are now experiencing large numbers of larvae in the leaf petioles of many crops. Phoma lesions and light leaf spot is particularly bad in some situations, requiring an early fungicide such as Toprex (difenoconazole + paclobutrazol) where thick crops also require a PGR. The paclobutrazol will help manage the canopy and allow better light interception to maximise yield potential. Other notable issues that are quite apparent is the amount of charlock in crops – particularly if the plant stand is low due to pigeon and deer grazing on field margins.
Hopefully we are still due a few frosts after an unseasonably warm period, which may help to alleviate this issue where an application of Fox (bifenox) under an Extension of Authorisation for Minor Use has not been possible before flower buds are visible.