Scourge in the Mediterranean: Phytosanitary policies against the Argentine ant in the first half of the 20th century

The Argentine ant ( Linepithema humilis ) is a Neotropical species from the Paraná River basin in central South America which has been spread unintentionally through human commerce from the nineteenth century onwards. It was soon recognised as an urban and plant pest and, more recently, as a threat to biodiversity in many of the places it has been introduced. This chapter analyses the causes of and motivations for controlling this species in Portugal, Spain, France and Italy in the first half of the twentieth century, describing and comparing legal and administrative measures among countries. Containment (in France), fight (in Italy) and eradication (in Portugal) were laid down in mandatory regulations dated from the 1920s, but none of these three aims were achieved. Despite a long history of control efforts, Argentine ants remain in Southern Europe and other invaded areas, where people still strive to control them.