More ware potato crops this season have been affected by the relatively rare bacterial disease Erwinia chrysanthemi, which produces similar symptoms to blackleg, according to packer MBM.

“We’ve seen it hovering around for a number of years, but there is definitely more about this year.

It is spread over more varieties,” says the firm’s Tom Dixon.

Varieties such as Victoria and Sante in particular have been hit, he says.

“It is affecting yield and quality. It is like blackleg, causing wilting and breakdown of stems, but it is not as aggressive in the tubers as Erwinia.”

Most cases are linked to Dutch seed, he says.

“It is very topical in the Netherlands this year too.

I understand at least 7% of their seed stocks have had to be downgraded because of chrysanthemi.

“They do have now very strict certification tolerances in the Netherlands, so hopefully it will be less of a problem and controlled through certification.”