POTATO GROWERS are being offered new hope in what seemed to be their losing battle against the potato cyst nematode.

With the soil-borne pest spreading exponentially, and already costing the Scottish potato industry £2 to 3 million per year, the common refrain has been that PCN is on course to wipe out profitable spud production in this country within 30 years, particularly as any chemicals that might have helped are too toxic to survive modern scrutiny.

However, the nematode has not reckoned with an intervention from the natural marine environment – the substance chitin, commonly found in shellfish shells. When included in a compost, the fibrous chitin is known to act as a biocontrol against PCN, and an effort is now underway to firm up its credentials as a weapon that can be more widely used by growers.

A group of farmers and researchers has been working with the Soil Association Scotland-led Rural Innovation Support Service on novel ways to manage PCN. One of them, Martin Cessford of Whanland Farm, Brechin, developed the chitin compost with others in the group as part of his agribusiness Angus Horticulture and is currently trialling it on his farm.

“We’ve applied the compost to a PCN-scheduled field and we’re monitoring the decline of PCN with a research station in Flanders, Belgium," said Mr Cessford. "Dr Andy Evans of SRUC got dispensation to use seashells from food waste 12 years ago, and in six years the fields were clear. We know it enhances the flora in the soil, we know it improves the soil, we just need to prove it!"

Mr Cessford started the group with Mark Clark of Grampian Growers, both of whom have struggled with PCN. “We stopped our daffodil business because of the risk due to PCN,” he continued. “It’s a global problem – it will annihilate seed potato growing within the next 30 years if we don’t get on top of it.

“The chemicals used to regulate PCN in the past are being slowly withdrawn – they’ve been found to be carcinogenic or they don’t help the flora in the soil. They’re either harmful to humans or the soil, so we need to look for alternatives.”

Soldier flies are another source of chitin that the group is exploring alongside shellfish.

SAOS facilitator Helen Glass said: “The group was farmer and supply chain-led and I’m proud of how they co-operated, and how Martin and Angus Horticulture grabbed the baton to set up meetings with academics and innovation centres.”

The RISS group has also developed work to improve soil sampling, with farmer Jim Wilson of Hilton of Fern, by Brechin, who runs precision agriculture company SoilEssentials. Alongside Scottish Agronomy and SASA, Mr Wilson's company received a Make Innovation Happen grant from Highlands and Islands Enterprise to take and analyse large volumes of soil for PCN.

“The industry has known for a while PCN was rising,” said Mr Wilson, “and we were all thinking there had to be a better way of dealing with it. The RISS group was a way of moving the problem forward and making a difference. We knew that unless we got together we would struggle to get traction.

“At SoilEssentials we use high intensity sampling to locate the PCN nematodes – they don’t travel far. It gives us a foundation – unless you know where the problem is and how big it is, you can’t make a plan to tackle it.”