Issued jointly with Fera
This is the time of year when the exotic Asian longhorn beetle is most likely to emerge from trees and shrubs, and the public are being urged to look out for it.
The insects’ larvae (grubs) cause serious damage to trees, and can kill them, by boring tunnels in the trunks and branches as they eat their way through the wood, before emerging as mature beetles. Not native to the UK, Asian longhorn beetle (ALB) and its larvae pose a serious threat to a wide range of broadleaved trees and shrubs such as maple, sycamore, elm, horse chestnut, willow, poplar, birch and some fruit trees
The UK’s first outbreak of breeding ALB was found earlier this year in the Paddock Wood area of Kent. As tree felling work to eradicate this outbreak is nearing completion, The Food & Environment Research Agency (Fera) and the Forestry Commission are asking the public to look out for these distinctive beetles during the emergence season, both in the Kent area and across the UK, to help prevent any outbreaks in the future.
Martin Ward, Head of Plant Health Policy at Fera, said,
“Although we are cautiously optimistic that we can successfully eradicate the Paddock Wood outbreak, we cannot afford to be complacent. At this time of year any larvae hidden undetected within trees or in the wood of boxes and crates will develop into beetles and lay eggs on other trees in the surrounding area. The public can really help us by keeping a lookout for these highly distinctive beetles, and reporting any findings.
“And we are not just asking people in the Paddock Wood to look out for them – these pests could turn up anywhere in the UK, especially where plants, and goods in wooden packaging, are received from China and Korea. All reports will be assessed by Fera’s Plant Health and Seeds inspectors and followed up as appropriate.”
Sixty-seven trees have been found infested in the Paddock Wood area to date, and more than 250 live larvae have been found inside these trees. Action to fell all trees showing signs of infestation, and precautionary felling of all at-risk tree species within the demarcated infestation zone, have resulted in the removal and incineration on site of more than 2000 trees.
The most recent finding of larvae was more than 20m (65 feet) up a tree and therefore undetectable without felling the tree, demonstrating the need for precautionary felling of all potential host tree species in the infestation area to give the best chance of successfully eradicating the outbreak. It is expected that the felling work will be completed by mid-August if there are no more finds. All felled material is being held locally for inspection before being incinerated on site.
The Forestry Commission has been co-ordinating the tree felling work in the Paddock Wood area, and Dr John Morgan, Head of the Commission’s Plant Health Service, said,
“It is always regrettable when we have to fell large numbers of trees to keep the UK free of invasive pests or disease and protect much larger numbers of trees. We have been extremely fortunate that local residents and landowners have worked with us to eradicate this outbreak.”
Leaflets are being distributed in the Paddock Wood and East Peckham area up to 2km (1.25 miles) from where the original outbreak was found. These include a picture of the beetle and details of what to do if one is spotted. The beetles are large (about 20 - 40mm / 0.75 - 1.5 inches long) and black with variable white markings. Their antennae are particularly distinctive, being very long (about twice as long as the body) with black and pale blue or white bands.
Horticultural and forestry authorities are also keen for anyone receiving trees and plants from China and Korea, or goods in wooden boxes and crates from those countries, to be extra vigilant for signs of the distinctive beetles emerging from the plants or boxes, and to report them immediately.
Anyone who suspects they have seen an Asian longhorn beetle, or evidence of its presence, must contact the Fera Plant Health Helpline by either:
Digital photographs may be sent with email reports to aid identification.
If possible, the beetle should be caught and placed in a secure container such as a sealed glass jar so that an inspector can collect it. The beetles are harmless to humans, although they should be handled with caution because they can nip the skin.
Further information is available from www.fera.defra.gov.uk/asianlonghornbeetle and www.forestry.gov.uk/asianlonghornbeetle.
NOTES TO EDITOR:
- The Asian longhorn beetle (Anoplophora glabripennis) is a serious pest in China, where it has killed millions of poplar trees planted to prevent soil erosion. An estimated $0.7 billion has been spent in the USA on campaigns to eradicate it there. The larvae of the beetle have been moving around the world hidden in timber imported from China, notably wood packaging material such as crates and dunnage, the timber blocks used to keep cargo from shifting in ships' holds.
- Up to the present outbreak, all the interceptions of live beetles in the UK had been found to come from wood packaging material. The Forestry Commission monitors wood packaging material, which is the main vector for this beetle, and this programme is kept under review in response to new or revised threats. The aim is to prevent introductions and outbreaks, but should one occur, it is tackled as a high priority. Information on the International Standard for Phytosanitary Measures No. 15 (ISPM15) on Guidelines for regulating wood packaging material in international trade can be found on the Forestry Commission website at www.forestry.gov.uk/forestry/INFD-6NJDRJ.
- ALB is almost identical in appearance to Citrus longhorn beetle (Anoplophora chinensis), another non-native longhorn beetle that threatens trees in Britain. Fera has produced a video about the Citrus longhorn beetle which can be viewed at
- The adult beetles scrape away a portion of bark on a host tree to lay their eggs just underneath. The lifecycle from egg to beetle is one to two years in Asia, and possibly longer in the UK. Adult beetles emerge in the summer, then mate, lay eggs and die. After hatching from the eggs, the larvae feed by boring in the trunk and main branches. This makes them difficult to detect.
- The most obvious symptoms of ALB damage are the circular adult exit holes, which are about 10 mm (0.4 inches) in diameter, and are usually found in the trunk and main branches. Other signs which might be present, but are much less obvious, include piles of sawdust-like droppings at the base of infested trees, scraped bark, sap bleeding from the sites where eggs have been laid, and bark-feeding damage on smaller branches and shoots.
- Not only do the larvae cause structural damage, but this damage also leaves the tree susceptible to other pests and diseases. Eventually this can lead to the death of the tree.
- The main known host tree species are maple, sycamore, horse chestnut, Mimosa silk tree, alder, birch, hornbeam, Katsura tree, hazel, beech, ash, golden rain tree, plane, poplar, cherry, plum, false acacia/black locust, willow, sallow, pagoda tree, mountain ash (rowan), whitebeam, American pin oak, North American red oak, and elm.
- Analysis of climate data by scientists at Fera suggests that most of England and Wales and some warmer coastal areas of Scotland are suitable for ALB establishment, but south-east England and the south coast are at greatest risk.
- Fera is an Executive Agency of the UK Government’s Department for Environment, Food & Rural Affairs (Defra). Its remit is to provide robust evidence, rigorous analysis and expert professional advice to government, international organisations and the private sector, in order to support and develop a sustainable and secure food chain, a healthy natural environment, and to protect the global community from biological and chemical risks.
- The Forestry Commission is the government department for forestry. It works to improve the lives of people through the many benefits which sustainably managed trees, woods and forests can provide. www.forestry.gov.uk.
- Fera - Alison Wilson, 01904 462380 / 07920 297631
- Forestry Commission - Charlton Clark, 0131 314 6500