Tree health authorities are appealing to the public to be on the alert during August and September for two species of beetle which could damage a wide range of trees and shrubs if they became established in the United Kingdom.
Eradication action taken against an outbreak of Asian longhorn beetles with the co-operation of local landowners in Kent last year appears to have been successful. Further monitoring will be carried out in the area over the next three years to confirm this, or deal with any remaining beetles. The earlier an outbreak is detected, the greater are the
chances of a successful response, and the smaller the area over which host trees must be removed to achieve eradication.
The call comes as part of wide-ranging efforts to step up the UK's defences against tree pests and diseases. Government is taking a range of measures, and action is already under way to implement two of the recommendations in the recent report of an independent Tree Health and Plant Biosecurity Expert Taskforce: a prioritised risk register and improved preparedness for dealing with outbreaks.
Work done so far on the risk register has confirmed that Asian longhorn beetle (ALB) and its close relative citrus longhorn beetle (CLB) represent a major threat, and that imported wooden packing material is a key potential pathway for these and some other tree pests.
Workers at places which might have received deliveries from Asia of tree and shrub plants, and goods in wooden crates and packaging, are being asked to watch for signs of the beetles. These insects could have been
accidentally introduced to the UK in such imports over recent years, particularly from China, Japan and Korea.
The summer months are the best time to spot the large black and white beetles as they emerge from trunks and branches, spread to other trees, and lay eggs.
Martin Ward, the UK Government's Chief Plant Health Officer, explained, "Government plant health services cannot do this work alone, and we need the public to act as our eyes and ears in gardens, parks, woodlands and workplaces to help us spot threats quickly before they become a serious problem.
"The public can really help us at this time of year by looking out for these two potentially serious beetle pests. They thrive in climates similar to ours, and their establishment could result in losses of trees from a wide range of species."
Dr John Morgan, Head of the Forestry Commission's Plant Health Service, endorsed Mr Ward's comments, adding, "There are strict controls in place to protect the UK against accidental introductions of these pests, but we need to back these up with constant vigilance and reporting of suspected cases. These beetles could threaten a wide range of ornamental, fruit and woodland trees, and the public and trade have a vital role to play in protecting our trees."
Adult beetles of the two species are very similar to each other, and easy to recognise. They are large and black with variable white markings, giving rise to the Asian longhorn beetle's alternative name of "starry sky beetle". Their distinctive antennae can be up to twice as long as their bodies (giving rise to the term "longhorn"), and are black
with white or light blue bands.
Anyone finding beetles should isolate them if possible (preferably in a sealed glass jar) and contact the Plant Health & Seeds Inspectorate (PHSI) of the Food & Environment Research Agency (Fera) by telephoning 01904 465625 or emailing planthealth.info@fera.gsi.gov.uk.
The PHSI should also be notified of any other signs of the beetles' presence, such as larvae exit holes in nearby trees.
Suspected sightings can be also reported using the Forestry Commission's 'Tree Alert' app or on-line reporting form available via www.forestry.gov.uk/asianlonghornbeetle.
The beetles are not harmful to humans, but should be handled with care because they can inflict an uncomfortable nip when handled.
Further information, including pictures, is available from www.fera.defra.gov.uk/plants/plantHealth/pestsDiseases/clb/index.cfm and www.forestry.gov.uk/asianlonghornbeetle.
Asian longhorn beetle facts
1. Single beetles of both species have been found in the UK from time to time, but the 2012 discovery of a breeding population of ALB in Kent was the first time an outbreak (a breeding population) had been found. Close working between Defra, the Forestry Commission, The Food & Environment Research Agency (Fera), local authorities and tree owners meant steps were able to be taken quickly to contain the outbreak before it could spread. The site is being monitored for four years for any signs of remaining infestation and to ensure the outbreak has been eradicated
successfully.
2. Introductions of the citrus longhorn beetle (Anoplophora chinensis) are mostly associated with the movement of plants for planting, while the Asian longhorn beetle (A. glabripennis) is most often intercepted in wooden packaging material used to transport products such as stone,slate and machinery from China.
3. Protection against accidental imports of ALB and CLB include requirements for treatment of wood packaging to kill any pests in it before it is exported to the UK or EU. Fera inspects all plant imports from outside the EU, and carries out routine surveillance checks on plants being traded in the UK. In May 2010, the EU introduced measures
to protect Member States against the introduction of citrus longhorn beetle. This included a suspension for two years of all imports of maples (Acers) from China, which were the main source of interceptions in the EU and UK. Since this suspension ended in May 2012, the beetle has again been intercepted in imports into the EU during 2012-13,
although not in the UK. The European Commission is liaising with China in response to these findings.
4. Although adult beetles are large and easy to detect and recognise, the larvae are not, because they live and feed inside the stems or branches of host trees, typically for one to two years in its native range (Asia), and possibly for as long as four years in Northern European climates such as the UK's.
5. The larval stage is the most damaging. The larvae feed on the pith and vascular systems inside the lower trunk and root, and the tunnels they make while feeding leave trees susceptible to disease and wind damage. Adult beetles cause more-limited damage by feeding on foliage and young bark.
6. Eradication campaigns are in place in other parts of Europe and North America where outbreaks have occurred. Canada and the USA recently announced the successful eradication of long-standing outbreaks in Toronto and New Jersey respectively.
7. CLB and ALB are on the list of six 'most unwanted' tree pests that school and community groups and volunteers are looking out for as part of the Tree Health Survey being conducted by OPAL (the Open Air Laboratory), in which Fera and the Forestry Commission's Forest Research agency are partners. For information and to take part, visit
www.opalexplorenature.org/TreeSurvey.
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