THE EFFECT OF POTENTIAL CLIMATIC CHANGES ON THE GEOGRAPHICAL-DISTRIBUTION OF THE PLANT-PARASITIC NEMATODES XIPHINEMA AND LONGIDORUS IN EUROPE

The data collected during the European Plant-Parasitic Nematode Survey which allows relatively detailed maps of the geographical distribution of virus-vector nematodes to be produced are used to analyse the relationship between the distribution of Longidorus elongatus, L. leptocephalus, L. macrosoma and Xiphinema diversicaudatum and the July soil isotherm in Great Britain and Europe. Results indicate a close association between temperature and nematode distribution and allow minimum, maximum and optimum developmental temperatures to be calculated. Predicted future climatic changes and in particular global warming show that nematode problems in northern Europe could intensify by an increase of the existing nematode populations and by the spread of nematodes from the south, but the rate at which this spread occurs is likely to be slow and dependent upon man's activities.