Pesticide red tape may prove 'a blight on the potato sector'

In Dundee yesterday, Barrie Florendine, of agronomy and chemical supply company UAP, said: "I see regulation having an effect on every single aspect of production."

Recent European Union pesticide legislation on product approval showed a general lack of understanding, he said. However, he added that at least initial fears that two-thirds of active ingredients would be lost had not proved correct. The level of loss was likely to be nearer a third, but it did include key chemicals such as the herbicide Linuron.

Blight control was also likely to prove difficult, with the tried and tested fungicide Mancozeb unlikely to be reapproved at its next assessment, while Chlorathalonil was likely to suffer from label changes.

Florendine said: "The lack of good blight-control products could be a problem. If climate change does mean a rise in temperatures of 1C, then we will need an extra ten to 12 days of blight protection in the season. The loss of fungicides puts real pressure on plant breeders to come up with resistant varieties."

Insecticides may fare worse, with the chemical armoury much reduced. He said: "In the absence of genetically modified varieties, insecticides are vital and I fear English potato production will be marginalised."

Meanwhile, Greg Cahill, of the Scottish Science and Advisory Agency, said:

"Blackleg is still the major cause of seed inspection downgrading in Scotland, but over much of Europe it is now dickeya." This potentially devastating disease is more virulent and damaging than blackleg. "In 50 cases discovered in England and Wales, all but two could be traced to seed from the Netherlands."

The good news was that no dickeya was found in any of 523 tuber samples of Scottish origin undertaken by the organisation's survey. More worrying was the discovery in 2009 of two crops with dickeya present, both grown from seed of non-Scottish origin. Of the 230 watercourses tested in Scotland, three were found to have dickeya bacteria.

Eric Anderson, of Scottish Agronomy, asked how these rivers had become contaminated. Were infected ware crops grown locally the source, or was it wash water from packing plants? Cahill was unable to answer definitively, but said no trace of dickeya had been found in waste water.

Paul Gans, a crop consultant from Cambridgeshire, said of Scotland: "Your inspection system covers much that is good, especially control of viruses Y and A, which can do a lot of damage in the fenland."

He suspected some early blight outbreaks on the fens might be linked to seed-borne infection. "It has to be taken seriously, because that is how epidemics can start."

He also asked Scottish growers to consider whether blackleg levels could be improved by limiting the number of generations in the seed chain and by having each crop in the ground for less time.