Abstract
FUNDING This is a European transnational research initiated via the EUPHRESCO (European Phytosanitary Research Coordination) ERA-Net (network of national funders of plant health research in Europe). The work is funded by the following countries: Austria, Belgium, Denmark, Germany, Italy, The Netherlands, and the UK (Defra and the Forestry Commission). The research providers from the UK are Fera and University of York (Defra funded) and Forest Research. The total project cost is 664,482 euro (approx. £558,164) over two years. POLICY BACKGROUND A. chinensis and A. glabripennis are EC listed longhorn beetles (Annex IAI of the EC plant heath directive 2000/29/EC). They are established in parts of Asia. Specific EU measures for the Citrus longhorn beetle (A. chinensis) were introduced in 2008 in response to repeated interceptions. The species are a threat to deciduous tree and shrub species in Europe, including fruit, ornamental and amenity trees; outbreaks are reported in several European countries (e.g. Austria, France, Germany, Italy and the Netherlands) and there are regular interceptions on imported trees, especially A. chinensis on Acers from China. A. glabripennis has been intercepted particularly on wood packaging material. Interceptions on bonsai material also occur. A. glabripennis has also been introduced to the USA and is under eradication there. Policy, Science and Operational needs: Research is needed to address the following policy and science needs and objectives: •Provision of validated, non-destructive detection tools for use by inspection services for a range of material, e.g. imported ornamental plants/trees as well as large mature trees. •Development of risk management approaches and development of policy (contingency plans, management options, legislation) in the event of outbreaks; these need to be based on sound science and potentially tailored to specific commodity types (e.g. alternatives to 2-year standstill notices in demarcated zones for valuable specimens such as bonsai). •Improved understanding of potential risks and impacts (risk assessment). STATE OF THE ART Longhorn beetles of the Genus Anoplophora originating in the Far East (primarily China, Japan and Korea) (Lingafelter and Hoebeke 2002), are wood-boring cerambycid beetles, with larvae feeding in the phloem-cambium region during the early instars and boring into the xylem of trees in later instars. They are highly polyphagous on trees and shrubs, and are able to colonise and kill both weakened and healthy plants. Larvae pupate in the wood and adult beetles emerge by boring an exit hole through the outer wood and bark. Newly emerged adults are not sexually mature and must undertake a maturation feeding period on twigs of trees. After maturation and copulation, females chew slits in the bark of living trees and lay their eggs individually (Lingafelter and Hoebeke 2002; Maspero et al. 2008). These xylophagous insects are able to complete their development in very small host material within one or two years depending on climatic conditions (Adachi 1994). There is an increasing threat of harmful impact in EU territory arising from the increase of material infested by CLB and ALB being imported and subsequently intercepted in nurseries. Evidence of ability to establish in the EU is provided by the list of new host plants attacked in Italy, France, The Netherlands, Germany and Austria in nurseries and also in gardens, public parks and woodlands (Haack et al, 2010). Detection Currently the only guaranteed method of detecting Anoplophora larvae is to destructively sample the suspect material. A number of techniques for non-destructive sampling are in various stages of development and show significant potential. Examples of this include an acoustic detection method developed in the UK and the use of biosensors (e.g. detection dogs) developed in Austria. Both these techniques require further investigation and validation, but could provide useful methods in the future. There are other potential areas of investigation that could potentially yield successful techniques, for example, utilising x-rays or other imaging based techniques. Diagnostics Anoplophora spp are readily identifiable as larvae and adults by suitably trained taxonomists. However, techniques for the identification of any organisms that have created exit holes in a tree or wooden material are less readily available. It is therefore unclear whether suspected infestations are from Anoplophora spp or from other native or exotic insects. Dispersal and Host Range Anoplophora spp. are highly polyphagous organisms and the list of potential host plants continues to grow. The potential speed of spread of an infestation or outbreak within European conditions and host plant distribution is unclear, but could be significant as, for example, evidence has shown that Acer negundo trees have attracted ALB adults over distances greater than 200m (Haack et al, 2010). Management Practices There are outbreaks of ALB and CLB across the world and many studies have looked at the efficacy of a range of management practices, including systemic insecticides, entomopathogens, physical and cultural control methods, boosting natural enemy numbers, tree destruction, fumigants and widespread monitoring of spread (Haack et al, 2010). Many of these techniques have shown promise in helping to contain or, in some cases, eradicate outbreaks. However it is clear that a more detailed understanding of these techniques and their potential under a range of eco-climatic conditions and host plants is necessary to enable contingency plans specific to the EU to be further developed. Biology in EU conditions The extent of the threat across the EU is driven by the ability of the beetles to both complete their life cycle and to do so at a rate that will enable significant population increase and spread. Climex models for Anoplophora spp. have been developed to estimate the area under threat, however there was a major review of Anoplophora (Lingafelter & Hoebeke, 2002) and the location data within this review has not yet been used. The potential distribution of A. chinensis has been studied within Pratique, regression models have been used at INRA and a new Climex model has been developed at Fera. The outbreaks of both A. chinensis and A. glabripennis in Europe and recent laboratory studies have led to a greater understanding of the relationship between temperature and the development of Anoplophora. The environment that Anoplophora larvae inhabit during their development (within trees) is insulated from the air temperature as measured by weather stations. To date, no attempt has been made to incorporate this insulating effect on the development rate of Anoplophora spp. Therefore the biology of these organisms in EU conditions has been investigated to a level which provides enough data for provisional assessments to be made but there remain many gaps in understanding.
United Kingdom