EARLIER drilling dates coupled with another mild winter – to date – have produced some of the best looking winter crops seen in recent years with the only sting in the tail being the resultant high disease burden and additional fungicides required to control them in the weeks ahead.

Add to that the problems linked with increased fungicide resistance and reduced efficacy of some chemicals and growers are having to look more to an Integrated Pest Management as a method of control.

It was a point highlighted by Dr Fiona Burnett, speaking at the SRUC/AHDB Agronomy Conference in Perth, who encouraged growers to consider varieties with high levels of disease resistance when looking at future crops.

"Disease risk amongst many of our winter crops is higher now than it's ever been due to last year's earlier drilling and warmer winter. We're already seeing yellow rust and septoria in many of the crops, and there is even some Tan Spot, which is more commonly seen on the continent" she said.

"We need to consider the options available to reduce the pressure on fungicides, because they are constantly under review, so there is definitely a need to pay more attention to varieties with increased resistance to disease."

She added that losses in pesticide availability are very much dependent on the classification of the endocrine disruptor at an EU level which may or may not be adopted by the UK, with other pesticides to include glyphosate, metaldehyde, chlorothalonil, cypermethrin and the neonicotinoids, lost due to other reasons.

Dr Burnett said that the best case scenario would see cereals, oilseeds and potatoes relatively unscathed, with the edible and ornamental horticulture sector badly hit.

Even the loss or restricted use of such chemicals makes control of weeds, disease and pests in key UK crops more difficult to control and that reliance on fewer actives could lead to pesticide resistance build up becoming more likely. As a result she encouraged the use of IPM plan to consider the timing of drilling and the weather conditions then right through until harvest. She also encouraged the use of crop rotations,

It is also important to make the best use of all effective fungicide groups, in mixtures and in sequences especially when there is now evidence that several cereal pathogens have evolved mutations in the SDHI binding site of succinate dehydrogenase.

“Although frequency of these mutations has, so far, been low, it provides compelling evidence of the need for united action," said Dr Burnett.

“The industry and science experts have come together and agreed anti-resistance guidelines for fungicides that are practical and easy to implement. The guiding principle is to make life as hard as possible for pathogens by avoiding overexposure to any one fungicide group. Certainly, SDHIs should always be used in balanced mixtures, never applied with weak partners or outside of statutory limitations. The addition of multisites to programmes also adds protection.

“It is more important than ever to follow FRAG-UK guidance, as it is the most effective way to slow the emergence of these mutations and maintain the disease control that growers need.”

Commenting on the use of fungicides on last year's wheat trials she said there had been good septoria control from the SDHIs but SDHI/azole mixtures much more robust for disease control and yield. Ascra Xpro gave improved septoria control over Aviator.

Straight SDHIs she said give moderate yellow rust control but are not as effective as Comet or Ignite, while SDHI, strobilurin and azole options all control brown rust, with Proline less effective than Ignite of Caramba 90. Proline, she said is the most robust azole for reducing the incidence of Fusarium head blight.

Regarding the barley trials, she said the SDHI/azole mixture, Siltra Xpro, maintained good control of diseases tested and more robust than straight SDHIs, with straight SDHIs ranging moderate to good in their effectiveness against rhynchosporium, however performance of Comet against rhyncho was weaker last year.

And, if you want a step away from the triazoles, Dr Burnett said Priaxor offers a non-azole option with good rhyncho control compared to established SDHI/azole mixtures.

Performance of straight SDHIs against net blotch was also weaker in 2016 compared to 2013-15 when there was low disease pressure, while Proline maintained good mildew efficacy last year.

The good news in oilseed rape crops following last year's results is that fungicide resistance to sclerotinia in the UK has not yet been reported with such chemicals generally still giving three weeks protection at high rates. However, there are azole sensitivity potential issues with.