Ascension Island Government

Government > News

Publication of the Evippe Risk Assessment

8 April 2024


The Ascension Island Government’s Conservation and Fisheries Directorate (AIGCFD), with support from the Darwin Plus-funded project, DPLUS134: Repelling the invader: turning the tide on Ascension’s Mexican thorn and CABI, obtained approval from the Governor on 22 February 2024 to release the Evippe moth as a biological control agent to control the spread of Mexican thorn on Ascension Island. Due to the high level of public interest in this subject, the full Evippe Risk Assessment is now available for viewing and can be downloaded from the AIG website:


This initiative is part of a strategic approach to manage the invasive Mexican thorn, which poses a threat to the island's biodiversity such as our green turtle and seabird nesting habitats, strongholds for the Ascension Island spurge, and endemic cricket population.


The approval from the Governor followed consultations with the public and Island Council in 2023. Extensive testing was also conducted including rigorous assessments of an extensive range of plants that have been tested for susceptibility to the Evippe moth during biological control programmes conducted in Australia and South Africa. In addition, plant species endemic or native to Ascension Island, plus a selection of species, including lettuce cultivated horticulturally or for ornamental purposes on Ascension Island have been tested as part of the DPLUS134 project. This ensures that the Evippe moth is highly specific to Mexican thorn and there will be negligible impact on other plant species.


The project is transporting its first cultured moths from the UK to Ascension on 10 April 2024. The culture will be kept at the culture facility already established in One Boat. Moths will be released at suitable sites around Donkey Plain and a monitoring program will begin to measure the impact of the moth along transects from the release sites. A Monitoring and Evaluation Plan has been drafted and will be published on the AIG website when finalised.


The AIGCFD were successful in applying for the Darwin Local project, BELEAF – Biocontrol: Evaluating Leaf-folding Evippe Activity on Flora. This project provides the opportunity to monitor the release and spread of the Evippe moth over a 12-month period and evaluate its effectiveness as a biocontrol agent against Mexican thorn. This is an extremely important next step in turning the tide on Mexican thorn and evaluating the success of the moth.


For further details, please contact the Mexican thorn Control Project Officer, Chrisna Visser on 66403 or email