PREPSYS covers a range of responses required to safeguard European ash and birch trees from future threats. Some of the key findings are highlighted below:
- The PREPSYS project conducted an extensive literature review and engaged with researchers and managers dealing with emerald ash borer (EAB) and bronze birch borer (BBB) to assess the ‘state of the art’ as a basis for potential invasion of Europe by these pests.
- Although there is increasing information on the two pest species, further work especially from a European perspective is required to both anticipate and to react to incursions of the pests. The PREPSYS project addressed key questions and gaps in our knowledge on the pests’ biology, control (including risks from transport of firewood, treatment of infested ash and biological control agents), dispersal and economic/environmental impacts.
- Using literature information and through an international conference held in Vienna, PREPSYS has pulled together the accumulated knowledge on EAB and BBB to prepare a European Toolbox for their detection and management. This can form the basis for a coordinated approach to deal with the very real threats from EAB and BBB.
- It is known from North America and European Russia that there is usually a gap of several years between arrival and first detection of EAB. PREPSYS has assessed the range of options for survey and early detection of EAB or BBB and concluded that girdling of trees (stressing the trees) is the most effective for this purpose. However, there are logistic problems in using this technique and so use of traps with chemical lures is often more practical; a range of traps is available with similar efficiencies in capturing adult beetles, although none provide an accurate measure of beetle population size.
- Management of infestations is usually through felling of infested or dead trees and this is an expensive and time-consuming procedure. Extensive research in North America indicates that slowing progress of infestations using trunk injections of the insecticide emamectin benzoate is an effective process to ‘buy time’ for selective felling and other measures. It is recommended that registration of the insecticide for use in Europe should be carried out urgently.
- In the longer term, introduction of parasitoids (natural enemies) from the native ranges of EAB is now becoming more effective after a slow initial period following release of parasitic wasp species from China and Russia. There is also detailed knowledge of the climatic requirements of these classical biological control agents and this has improved establishment and efficacy. Since there is a need for assessment of possible adverse impacts on non-target species, tests for potential use of these agents in Europe should be carried out urgently. Methods for mass production are, fortunately, already developed in the USA.
- Efforts to increase outreach and involvement of the local authorities and the public in detection and reporting of infestations should be increased. In particular, both hard-copy and on-line resources for Europe should build on the extensive knowledge base that has accumulated in North America. The scope for use of citizen science should also be investigated at local and national scales. Explanation of management measures (felling of infested trees, insecticide usage and release of natural enemies) should be enhanced to provide up to date information and encourage support by the public for such measures.
- There is an increasing zone of overlap between EAB and ash dieback caused by the fungus Hymenoscyphus fraxineus in Western Russia. A key question is whether the interaction between the two organisms will affect total tree mortality. Support for joint research into this interaction should be provided urgently.
- The tools for the toolbox are becoming more effective and sophisticated. However, there needs to be greater coordination and ‘ownership’ of the toolbox. EU DG Santé and EFSA, along with EPPO, are ideally placed to guide action plans and to provide financial and logistic support. National Plant Protection Organizations (NPPOs) can influence this process. Outcomes from PREPSYS have provided the key topics that could provide a management strategy for Europe. However, ownership of a future strategy in Europe remains at National levels and requires close coordination