What is PCN?

What is PCN?

Potato cyst nematodes or PCN are a major potato pest. They can be found in most potato-producing countries around the world. There are two types of PCN, Globodera pallida and Globodera rostochiensis

PCN feed and reproduce on potato roots. This can cause poor growth, wilting, and early senescence in a potato crop, all factors which will impact yield and quality. Symptoms are not usually seen in field at low levels of infestation. Soil sampling is used to detect if PCN is present in an area of land and what species. PCN are measured in eggs per gram of soil and they are spread via infested soil attached to machinery, tubers, footwear, and through water movement.

Current Control Measures for PCN include:

  • Growing varieties that are resistant to the species of PCN present.
  • Maintaining a high level of hygiene to minimise the movement of PCN.
  • Extending rotations as PCN will naturally decline between potato crops.
  • Controlling groundkeepers, which are volunteer potatoes, as these will act as a host between potato crops helping to maintain the population.
  • Trap cropping which encourages eggs to hatch in the absence of a host plant.
  • Biofumigation which suppresses soil-borne pests through the release of gases.
  • Nematicides to protect potato yields in PCN-infested fields.


Most of these control measures are being investigated and developed within this project. To find out more, click on the Work Packages tab.

Why is the potato industry worried about PCN?

  • PCN can reduce yields by up to 80%. This is a significant loss in a crop that is expensive to grow and requires a high number of inputs. 
  • Seed potatoes must be grown in soil that has been tested and found to have no PCN cysts present. 
  • The area infested with Globodera Pallida is doubling every 7 years in Scotland, meaning there is a less land available for producing seed potatoes.
  • There are fewer resistant varieties available to control G. pallida than G. rostochiensis.
  • Nematicides are widely used, but if they are banned in future, yield losses due to PCN will increase. The efficacy of non-chemical control options such as trap cropping and biofumigation is still being determined.


More information about PCN can be found in the Introduction to PCN Factsheet. 

PCN Introduction Factsheet FINAL_0.pdf