Catchy weather is dragging harvest out in some cases, affecting field work for following crops. Although many growers completed harvest during better weather at the very beginning of September there are still fields of wheat, beans and spring barley to cut at the time of writing.
As a result there is a wide drilling window for oilseed rape, from early August-drilled crops at 3-4 true leaves to seed still in the bag. Rape that has been sown has established well with plenty of moisture and have been treated pre-em, or more commonly post-em, with a residual herbicide plus graminicide where volunteer cereals have emerged with the crop.
Phosphate deficiency is visible on low P index soils and areas of fields. Where DAP or an NPK fertiliser hasn’t been applied in the seedbed these crops are being treated with foliar phosphate products to improve rooting and canopy expansion.
Predictions of higher dormancy in blackgrass this season seem to be holding true as there has been little blackgrass emergence in rape so far. This time last year we had a huge flush of blackgrass emerging with the crop. Having said that stale seedbeds behind rape were starting to produce blackgrass towards the very end of August.
The worst fields have been sprayed off with glyphosate and will be targeted for slightly later drilling to allow a second glyphosate treatment. Cultivations have generally produced very good conditions for final seedbed preparation and drilling in due course.
In most cases the grassweed herbicide strategy will be based on stacking and sequencing residual herbicides to take the pressure off iodosulfuron/mesosulfuron. In cases where target site resistance to Atlantis occurs we will be reliant on the stacking/sequencing strategy coupled with cultural control. This approach worked very well last year where it was the only realistic option.
Slugs are evident in rape stubbles and the damp conditions are encouraging them elsewhere. Control strategies are based on staying within the 210g metaldehyde a.i. advisory limit by concentrating carefully on baiting points delivered by different products.
Using quality pellets that last longer in the field and retain the active ingredient better should reduce repeat applications. Low a.i. pellets (1.5%) are also likely to play a part and possibly ferric phosphate in the most environmentally sensitive areas. Deter-treated cereal seed also forms part of the overall strategy but this will almost certainly be combined with an application of pellets as pressure seems to be building compared to last autumn.