Abstract
Apart from aphids and scales, 52 additional Sternorrhyncha hemipteran species alien to Europe have been identified within Aleyrodidae (27 whitefly species), Phylloxeroidea (9 adelgids, 2 phylloxerans) and Psylloidea (14 species of jumping plant-lice) in addition to 12 Auchenorrhyncha species (mostly Cicadellidae- 8 species). At present, the alien species represent 39% of the total whitefly fauna and 36% of the total adelgid fauna occuring in Europe. The proportion is insignificant in the other groups. The arrival of alien phylloxerans and adelgids appeared to peak during the first part of the 20th century. In contrast, the mean number of new records per year of alien aleyrodids, psylloids and Auchenorrhyncha increased regularly after the 1950s. For these three groups, an average of 0.50.6 new alien species has been recorded per year in Europe since 2000. The region of origin of the alien species largely differs between the different groups. Alien aleyrodids and psylloids mainly originated from tropical regions whilst the adelgids and phylloxerans came equally from North America and Asia. A major part of the alien Auchenorrhyncha originated from North American. Most of these alien species are presently observed in man-made habitats, especially in parks and gardens but alien adelgids are mainly observed in forests because of their association with conifer trees used for afforestation.