Abstract
Molecular examination of the ribosomal internal transcribed spacer (ITS) region in potato cyst nematodes (PCN) is described. The ITS was amplified and sequenced from a number of PCN collections. A low level of sequence variation was found between Globodera rostochiensis, G. pallida, and a Peruvian PCN collection, but no variation within Australasian collections of species was noted. Polymerase chain reaction (PCR) primers based upon the G. rostochiensis–G. pallida sequence differences were designed and successfully used to identify mixed PCN species in a single PCR reaction.