Potato cyst nematode (PCN) has been found in Western Australia and Victoria. Populations of PCN that were studied by this project belonged to one species (Globodera rostochiensis). Extensive testing of a range of resistant potato genotypees showed that the populations did not have any potential to develop virulence. This finding will enable Australian potato breeders to focus on a specific set of resistance genes. A sensitive, specific PCR-based test was developed to detect the presence of both species in a mixture of nematodes. The test is also capable of determining which species of PCN is present.