Trends in Arthropod Eradication Programmes from the Global Eradication Database, Gerda

Abstract

The Global Eradication and Response Database (GERDA, https://b3.net.nz/gerda) documents representative incursion responses and eradication attempts against tephritid fruit flies of economic importance, Lepidoptera, tsetse flies, screwworm flies, mosquitoes, ants, beetles and other particular taxa of invasive arthropods since 1869. It includes cases where governments were quickly resigned to the inability to eradicate, as well as cases where a positive outcome was sought in a declared eradication programme. The distribution of pests is expanding well beyond what has been recorded in GERDA, but this information contains useful trends. The rate of eradication attempts continued to rise during the 20th and into the 21st century. In the case of Lepidoptera other than gypsy moth, 75% of programmes were started in the last 20 years. This is evidence for the rapid geographic range expansion under globalisation. It also indicates how active risk analysis and improved technology are increasingly enabling governments to attempt eradication to avoid projected substantial long-term costs of pest establishment. More than 80% of eradication programmes have been successful for arthropods in the database. For certain groups such as tephritid fruit flies of economic importance, the success rate is even higher, due to the experience gained from previous similar programmes, as well as the progress in the development of lures and suppression tools. A steady increase in the number of eradication programmes globally suggests that current exclusion measures for constraining the spread of invasive species are not adequate. Cost-benefit analysis based on prior pest behaviour indicates that additional mitigation against certain taxa are warranted (if possible). It is likely that all these reasons have led to this increase in the number of eradication programmes over time as a consequence of increases in travel and trade volumes from an expanding number of countries, a desire to maintain or reduce pest pressure on exotic and native commodities, and the development of new tools to increase the technical feasibility of eradication attempts. It is notable that arthropod eradication programmes still rely significantly on insecticides, but their importance is steadily decreasing when compared to the application of other tools.