This report details the research undertaken to aid in the differentiation of biological variants or pathotypes within the potato cyst nematode (PCN) species complex. This work is of direct relevance to the potato industry in Australia as PCN is a quarantine soilborne pest of potatoes which has now been detected in two Australian states, including Victoria, the largest potato producing state. The best strategy for control of PCN is to plant resistant potato cultivars, combined with long crop rotation schedules.