Potato rot nematodes are identified and diagnosed by various morphological and molecular methods. The morphological methods are the primary means of diagnosis, with molecular methods being used for when there is a low level of infestation or when only juveniles are present. Nematodes are extracted from infected plant tissue and examined microscopically for distinguishing characteristics such as body and stylet, and tail morphology. Molecular methods for identifying "Ditylenchus destructor" (especially in distinguishing from other Ditylenchus species) include PCRs (polymerase chain reactions) to find restriction patterns of DNA to identify specific species.