Potato Wart Pathotypes in Europe from the Ecological Point of View

The paper gives a survey of the foci of aggressive pathotypes identified and published so far in Europe (Czechoslovakia, FRG, GDR, USSR). It reports on 17 pathotypes mainly localized in montane and submontane regions of Central Europe with a more continental climate. Most of the foci lie at altitudes above 400 m with annual precipitations above 600 mm, on weathered more acid soils of illimerized type localized in small gardens and small plots. The problem of the appearance and extinction of foci of the common and more aggressive types is discussed together with possible explanations for foci in apparently atypical localities.