COST Action FP1401 – Global Warning
Most countries regulate organisms based on their actual or potential economic and environmental damage, established through Pest Risk Analysis (PRA). Consequently, only few, known species are regulated, but there is little overlap between the identity of regulated and established species. In fact, many, if not most of the established pests and diseases were not known to be harmful in the region of origin, or were unknown to science prior to causing serious damage, and hence were not regulated before they invaded (Kenis et al. 2007). This problem indicates that the current system to identify and regulate potentially harmful species is too weak to protect the environment and the economy from damage by invasive alien species (IAS). An early warning system that identifies potentially invasive tree pests and diseases in the exporting country would allow PRA to be carried out and measures to be stipulated and taken in the exporting country to reduce the level of contamination.
Many countries carry out a risk analysis on pathways of introduction or commodities (e.g. plant genera, species or varieties from a specific origin) before issuing import permits for the commodity. In Europe, by contrast, risk analyses are carried out to inform decisions on the regulation of individual pests and are focused on known species. PRA and pathway risk analysis requires, amongst other information, data on pest-host associations. Usually, however, the quantity and quality of information about organisms associated with plant species is restricted to known, damaging pests associated with the plant species in the region of origin, but this is not sufficient to assess whether these pests and pathogens will be a threat to the environment in the importing country. Moreover, potentially harmful pests may not be recognised during risk analysis because they do not cause serious damage on co-evolved hosts in the region of origin. When they encounter new hosts without a shared evolutionary history, the new host plants can be extremely vulnerable to attack compared with the native hosts in the region of origin. An example is the recent invasion by the non-European pathogen Hymenoscyphus pseudoalbidus on European Fraxinus. Whether host jumps will occur after introduction of IAS and to what extent the environment will be damaged are almost impossible to predict. An early-warning system based on European trees in regions that export live plants to European countries will provide an assessment of the vulnerability of these species to pests and diseases from the exporting country before they arrive in Europe.