Potato cyst nematode (PCN) has caused huge problems for the industry for decades and with no real control method, the situation will only magnify before it deteriorates.

That was the stark warning from Jon Pickup of Science and Advice for Scottish Agriculture (SASA) who said that the amount of ground infected with PCN has increased by 13% in recent years and is expected to rise further.

"Some 150,000ha of ground in Scotland is used to grow potatoes and 20,000ha of that is infected by PCN, " said Mr Pickup, speaking at the SAC Association of Potato Producers Annual Conference, in Scone.

"Most of that (15,000ha) is made up of the species Rostochiensis, with the remainder (5000ha) being Pallida – which although has been found in small populations up until now, is set to soar.

"Pallida which was originally concentrated around the Dundee area is spreading up the coast and is likely to double in the next six to seven years whereas Rostochiensis levels appear to have plateaued.

"What you have to ask yourselves is can the industry cope with up to 20,000ha of ground infected with Pallida in Scotland by 2031?" Mr Pickup questioned pointing out that the pest causes £26m worth of damage to crops in the UK every year as it is, and can result in yield losses of up to 80%.

He said the big problem lies with the fact that only 2% of the potatoes grown are resistant to the Pallida species compared to 50% of the potatoes produced that are resistant to the Rostochiensis.

As a result, Dr Matt Back, a reader in plant nematology at Harper Adams University urged producers not only to consider growing more resistant varieties but also to think about control at all times. He also stressed that that just because a field comes back with 'undetected PCN', does not mean the field is clear of the pest.

"PCN is still a major threat due to the complexity of the pest. You have to understand the populations and the species in the field and grow varieties that are tolerant or resistant to the species.

"Rotation length is critical but not always feasible. You also have to remember that PCN can be there in a field for 20-30 years and will spread to other fields by machinery. Therefore, clean your machinery every time it comes out of a field," he said.

* New findings from on-farm trials have recently found a new method to control PCN.

Following field trials carried out by AHDB Potatoes and Harper Adams University, fluopyram, which is normally used as a fungicide, was shown to increase yields in a range of potato varieties with high levels of PCN when used as a nematicide.

Speaking at an AHDB Strategic Potato (SPot) day, Anne Stone said the use of nematicides gave a highly significant yield increase across the varieties planted.

“We saw interesting results that may suggest varieties display different relative levels of tolerance at different infestation rates," she said.

"The new Bayer product, which contains fluopyram, was compared with Nemathorin and Vydate. It performed as expected, showing a yield increase compared with an untreated control, though the other nematicides outperformed it.

She added that the results were consistent to trials elsewhere which have shown that used in isolation, the new treatment is less effective than others under high pressure situations.

"The new product provides an extra line of defense against this resilient pest, and is also easy to apply.”

However, Bayer is not promoting it as a single-use solution in extreme situations, but as part of a programme with conventional nematicides and resistant varieties. Instead, while fluopyram has been shown to reduce cysts and eggs, the company claims it provides an opportunity for those with low to moderate PCN infestations an opportunity to combat populations and will form an important part of their nematode control strategy”.