Young potato plants growing in a field © Tim Scrivener© Tim Scrivener

The total area of land blighted with the potato crop’s most costly and damaging pest is in decline, according to new survey results.

Of the soils tested in 2016, the survey showed nearly half (48%) were infested with potato cyst nematode (PCN), a decline of 16% on the previous figure.

The pest costs the UK potato sector an estimated £30m/year in significant yield penalties, making it one of the top headaches for British spud growers.

See also: How biofumigant crops cut nematode numbers in potatoes

Carried out by Kasia Dybal of Harper Adams University as part of a AHDB Potatoes PhD Studentship, the assessment of UK soils is the first conducted since 1999.

H1 resistance gene

Harper Adams University’s Matthew Back said the fall was potentially due to the increase in potato varieties carrying the H1 resistance gene to the Globodera rostochiensis nematode species. 

This is one of two species of PCN, the other being Globadera pallida.

“The widespread use of varieties with high resistance to G rostochiensis, possibly combined with the adoption of better management, including longer rotations, adoption of better practices and integrated management techniques, has led to an overall decline in the area infested,” said Dr Back.

Also highlighted was a significant shift in PCN populations that remain in affected soils, with almost 90% of infested sites containing purely the G pallida species.

This is a big rise compared with the 1999 figures, when the G pallida species accounted for 67% of infestations.

Dr Back highlighted that until recently, commercial varieties have predominantly had resistance to G rostochiensis only.

 

With six of the 10 most common potato varieties grown in the UK, including the country’s most popular, Maris Piper, having high resistance to the G rostochiensis nematode species, Dr Back said the upshot is that growers are left with more G pallida to tackle in their soils.

“Varietal resistance is a key component of PCN management. The processing sector has access to quite a few resistant varieties, but very few options are available for the ware sector.

“Of the top 10 varieties, two score 3 for resistance and the rest just 2,” added Dr Back.

Eventually the aim is to map PCN distribution across the UK, highlighting regional differences in populations to help growers pick the best varieties for their area.