Invasion of non-indigenous insects: the impact of quarantine laws

The success rate of invasive species control programmes is usually inferred from the species identification record. However, identifications may not happen concurrently with species introductions. Some species prevented from arriving also remain undetected by authorities. This study accounts for these possibilities and provides an estimate of the historic success of quarantine laws at limiting introductions of invasive insect species. The processes of species introduction and identification are estimated jointly, using data on international trade, immigration, USDA outlays, and enactments of quarantine laws. Historic trends of species introductions and would-be introductions prevented thanks to quarantine laws are inferred. Various forms of trade flow, and quarantine laws are found to have a significant impact on invasive species' introductions.