Opportunities for early grassweed control look fantastic – the complete opposite of autumn 2009. With the main bulk of cereal drilling now underway crops are generally being drilled into well prepared land that is resulting in good quality clean seedbeds.
Even where considerable amounts of blackgrass have been wiped out with glyphosate pre-drilling the priority will be to apply a pre-emergence herbicide for grassweed control. Supply issues mean that some careful targeting of the premium herbicides is required in conjunction with closely considered tank mixes.
Slug pressure in oilseed rape has so far been relatively low although slug damage has been showing up in some of the later till-seeded crops on heavier soils. Hopefully good firm wheat seedbeds after rape where Deter has been used will take some of the pressure off metaldehyde in these higher risk situations.
Oilseed rape has experienced a wide drilling window this season with mid-August drilled crops at 4 leaves plus. Downy mildew was evident in these earlier crops at cotyledon/first true leaf stage but perversely the later drilled crops presently look fairly free of mildew. Nevertheless conditions are conducive to phoma development so the earlier crops are being carefully monitored for first signs of disease.
A low dose fungicide will be applied at first signs of disease – where this is applied early a second treatment may well be required to ensure the crop is disease-free going into winter. With rape prices where they are at the moment a very small yield increase is required to cover the cost of the autumn fungicide program. The blackgrass sprayed early post-emergence looks very sick. Even if not fully controlled these blackgrass plants will be smaller and more susceptible to propyzamide/carbetamide once we reach suitable conditions for application.