SCOTLAND’S POTATO industry could be wiped out by 2025 by the growing threat of Potato Cyst Nematodes, Soil Association Scotland has warned.

A group of 42 growers, farmers, and industry representatives from across Scotland met in Angus as part of a new Soil Association Scotland-led Rural Innovation Support Service group, looking to find solutions to save the sector.

Around 5% of seed land in Scotland is currently infested by the well-known potato pest and around 33% of untested ware land is also suspected of PCN. With a longevity of 25-30 years, infested land can be rendered commercially useless for potatoes during some of that time.

The meeting saw speakers from SAC Consulting, SRUC and SASA outline the available data on the spread of PCN and potential control methods, followed by group discussions on viable options to halt the spread of infested land.

The pallida species of PCN is a particular concern, with the amount of infected land doubling every six or seven years and it is predicted that it may take up to 30 years before infestations decline to allow seed potatoes to be grown on that land again. Speaker Jon Pickup of SASA said: “We’re seeing an exponential increase in our findings of pallida in Angus alone. We’re finding PCN in about 500 hectares per annum, but the exponential spread means that by 2025 this could be at 1400 - 1500 hectares. With six-year rotations, the management decisions we make now will only change things from 2026 onwards.”

He added that growers are losing £2 to £3 million per year in seed potatoes and a built-in £5 to £6 million loss by 2025.

A long-term solution discussed was the need to grow varieties of potato resistant to PCN. However, of the top 15 major Scottish varieties of seed potatoes currently grown, only Innovator and Royal varieties are resistant to pallida, and issues with demand exacerbate this problem.

Kim Davie of SASA explained: “Most pallida-resistant varieties are processing varieties, but in Scotland our ware market is for table varieties. There are only a few pallida resistant varieties currently suitable for use as table varieties and the question is, how do we get supermarkets to take these resistant varieties? It’s getting people wanting to buy them and getting companies wanting to sell them,” she stressed.

Dr Andy Evans of SRUC suggested soil sampling as an option for controlling PCN short term but highlighted that Scotland’s climate would prove to be a hurdle: “The best approach really is to know what you’ve got. Sample fields to get an idea of the PCN species and population.

“If you’ve got high egg counts, you really do need to think about a long rotation of 10 to 13 years, grow resistant cultivars, and consider biofumigation or trap cropping. If you’ve had a low PCN count and grown a resistant variety, it’s still worth resampling after the potato harvest to see where you are. It’s better to take a sample immediately after a potato crop,” he urged.