When soil samples are examined for potato cyst nematode (PCN) the results are averages based on the cores taken from various places in the area sampled. Since nematodes are not evenly distributed across a field so some parts of the area may differ noticeably from the average.
Each soil sample is assessed for the presence of cysts and this is expressed as a cyst count per 100g of air dried soil.
Cysts contain eggs and it is the larvae from these that attack the potato crop. The number of eggs is expressed as eggs per gram of soil.
View or download the Potato Cyst Nematode Testing Bulletin as a PDF.