Exotic Scale Insects (Coccoidea) on Ornamental Plants in Italy: a Never-Ending Story

The introduction of ornamental plants into Italy for commercial and hobby purposes has provided scale insects with many chances of dispersion. Coccoidea often go unnoticed at border controls due to their cryptic lifestyle. Moreover, many of the introduced alien species become acclimatized outdoors, possibly due to the effects of urban pollution and global warming. The authors attempt to analyse this phenomenon and report on the records of new alien species in Italy, starting from the end of the Second World War. In the period 1945-1995, an average of 0.64 new introduced alien species were reported per year, whereas an average of 0.7/year were introduced between 1995 and 2005 and 1.25/year since 2005. About fifty alien species have been recorded so far in Italy, of which about 50% are presently acclimatized on ornamentals. The increase in alien species introduction is probably due to: the ever easier and faster transport and dispatch of plants in a globalized world trade; the free movement of goods within the European Union; and the weakness of the National Plant Protection Organization (NPPO) monitoring. Moreover the effect of global warming may have played an important role, directly enhancing the survival and development of the insects in their new environment. The authors comment and discuss the more invasive species, namely Ceroplastes japonicus Green, C. ceriferus Fabricius, Protopulvinaria pyriformis (Cockerell), Phenacoccus madeirensis Green, Phenacoccus peruvianus Granara de Willink, Phenacoccus defectus Ferris, Chrysomphalus aonidum L. and Aulacaspis tubercularis Newstead.