Potato Cyst Nematode Analysis

Potato Cyst Nematodes have been known to occur in the UK for nearly one hundred years. They are the most problematic pest of potatoes and can cause a severe yield loss.

Advice for PCN Sampling

Samples of soil should be taken using a soil corer.

Fields should be subdivided into blocks of one hectare or less, sampling in a grid using a ‘W’ pattern is deemed the most effective, across the direction of cultivation.

Approximately 1.5 – 2 kg of sample are required by the laboratory for analysis, if a sample is deemed lightweight we may contact you to discuss further action.

For a 1 in 6 crop rotation it is suggested that at least a 200gm sample be analysed


Potato Cyst Nematodes are not evenly distributed across a field so some parts of the field may have higher than average numbers present resulting in ‘hot spots’. Some areas of a field may have low counts, so the results shown refer only to the sample received in the laboratory.

It is essential to follow the recognised sampling procedures. AHDB have published guidelines PCN – sampling and Laboratory Guide. Sample guidelines are available on request from the laboratory.

Download the field form

PCN sampling requirements

The preferred sample weight for PCN analysis is 1.5kg and for PCN/LOAM analysis is 2kg.

All results of PCN analysis must be interpreted in conjunction with:

  • The past history of the field
  • Last year’s potatoes grown
  • Variety of potato grown
  • Any problems in previous potato crop relating to PCN
  • Any use of nematicide
  • Presence of Deadly Nightshade

Bags can be supplied and posted out.