Abstract
The potential of antigenic differences for discriminating pathotypes of the potato cyst nematodes Globodera pallida and G. rostochiensis has been examined by the use of an antiserum raised to a homogenate of potato cyst nematode larvae. Species-specific antigens were detected among reference pathotypes but more variability was detected among field populations, and cluster analysis was used to interpret the precipitation are pattern produced by Laurell crossed-immunoelectrophoresis. A division into species was seen with this analysis but no definite pathotype groupings were detected. Cross-reaction with other cyst-nematode species was limited to general non-specific precipitation. The antigens were all proteinaceous, did not arise from micro-organisms within the cyst and were mainly hydrophilic with an acidic isoelectric point. Peptidase and acid phosphatase activity was detected in some precipitation arcs but this was not species specific.