There have been two distinct drilling windows for wheat this season. September-drilled wheats went into excellent seedbeds and pre-emergence herbicides where applied have worked very well. In some places it is possible to see the effect of extended heavy rainfall after residual herbicide application.
Where blackgrass has emerged through the pre-em treatments, we will be looking to tidy this up with mesosulfuron + iodosulfuron whilst conditions remain suitable for application.
October drilling has resulted in more variable seedbeds especially on heavier land where some crops will have to be sprayed early post-emergence due to cloddy seedbeds and poorer soil coverage.
These later drilled wheats are less likely to have a mesosulfuron + iodosulfuron treatment this side of Christmas – a considerable proportion of the blackgrass population was taken out pre-drilling with at least two applications of glyphosate following repeated grassweed flushes.
Slug activity has increased since rainfall in early October, but crop damage and slugs are patchily distributed allowing pellet use to be carefully targeted.
Oilseed rape growth stages vary considerably, but any crop that hasn’t yet had a fungicide treatment is showing phoma lesions. The priority on these crops is to apply a fungicide as soon as possible.
Soil temperatures are still too high for propyzamide or carbetamide to persist long enough within the rooting zone of grassweeds to achieve satisfactory control. However, there will be a temptation to apply these residuals in those fields where blackgrass populations are high and weeds are large. If this decision is taken it must be with the understanding that a fallback position may be required ie to apply a follow up treatment if the first one fails. This is not a good strategy from the point of view of cost or the environment.
For those willing to wait until soil temperatures reach 10C, at the present rate this is not likely to be until the second week of November.