With the nights now drawing out, lambs appearing in fields and daffodils starting to bloom, one might start to feel the promise of spring in the air. A very welcome feeling.
Out on-farm, crops are being walked to determine the success of autumn weed control and the presence of disease.
Growers are starting to apply fertiliser and prepare spring ground. I am advising that first fertiliser applications should target oilseed rape, second wheats and any backwards cereal crops. Winter barley will also require early nitrogen to ensure no tillers are lost through inadequate soil nitrogen.
Powdery mildew can be found in forward cereal crops, however frosts in January have helped to control this early infestation. In winter wheat, septoria can be found on older leaves, but levels are currently low and little movement of the disease has occurred up the plant. Many varieties on the recommended list have good disease resistance ratings to yellow rust, however yellow rust can be found on more susceptible varieties such as Santiago and Cordiale.
Again, frosts have helped to slow the spread of disease. While no fungicide treatment is required at this early stage, growers need to be prepared to treat for yellow rust and mildew in susceptible varieties at T0.
In oilseed rape crops, some of the more susceptible varieties have phoma re-infection. However, further fungicide applications for this should not generally be required unless plants are very small and backward. Of more importance is the development of light leaf spot, with disease pressure starting to increase.
Light leaf spot manifests itself as small white spots in groups on the leaf. These then form lesions with pinkish centres, with more spore-forming spots surrounding these lesions. Light leaf spot can be hard to identify. To confirm if lesions are light leaf spot, incubate the infected plant leaf for 24 to 48 hours to encourage the rapid development of the distinctive white spore droplets around the lesions.
Close monitoring of fields is required to identify suitable fungicide timings. No treatment threshold exists for light leaf spot, but ideally a fungicide should be applied at the first signs of the disease as the only chemistry available is protectant rather than curative.
If crops are inadequately protected, light leaf spot can spread through the plants affecting leaves, stems, flowers and pods. Untreated crops can suffer yield losses of more than 50%. While incidence so far this year has been low due to the relatively dry winter, it is important to remain vigilant.
With conditions favourable for spring drilling, many growers will now be contemplating drilling spring cereals. Careful thought must be given to the development of the crop, particularly in spring barley where grain yields relate more to factors affecting early growth than late.
Unlike wheat, barley has a limited ability to compensate for reductions in seed rate as each spikelet only holds one or three florets. Drilling date, seedbed and plant establishment, therefore, are crucial to ensure the success of the crop, with tiller production and survival being the most important factors in determining yield in spring barley.
Early nutrition is crucial and the application of nitrogen to the seedbed should be routine. Application of phosphate and potash to the seedbed in spring will also influence root development and crop establishment. It is also important to ensure the crop is not limited by disease or lack of nutrients at tillering to ensure the survival of all tillers.
With the unpredictability of the weather (the Beast from the East last year did not arrive until the start of March), it is important to address every aspect of early crop establishment to ensure you give your crops the best start to the season – from seed rates to seedbed conditions, attention to detail is key.