Asian longhorn beetle (ALB) is a native of China and the Korean peninsula, and poses a serious threat to a wide range of broadleaved trees. It has caused extensive damage to trees in the USA and Italy since being accidentally introduced there in recent years, and there have been outbreaks in several other European Union countries.
The beetles tend to stay close to the site of original infestation in the early stages of an outbreak. However, the beetles can fly more than 2km. Analysis of climate data suggests that south-east England and the south coast are at greatest risk of these beetles establishing colonies.
Individual specimens of Asian longhorn beetle have occasionally been found from time to time in the UK, but in March 2012 a breeding population was confirmed near Maidstone in Kent. Fortunately this outbreak was detected before the 2012 adult beetle emergence period, but the beetle is considered such a potent threat that a total of 2166 host trees were removed, of which 66 were found to be infected.
Susceptible species include maples and sycamores, horse chestnut, alder, birch, hornbeam, hazel beech, ash, cherry, plum, poplar, whitebeam and plane. Apple and pear trees may also be affected.
ALBs are about 20 – 40 mm long and shiny black with white markings. They have distinctive antennae, which are up to twice their body length and black with white or light blue bands.
Adult emerging beetles leave 10mm circular exit holes in trunks and branches of infested trees. Other less obvious signs of infestation include piles of sawdust-like droppings at the base of infested trees, scraped bark, sap bleeding from sites where eggs have been laid, and feeding damage on the bark of smaller branches and shoots.
You are legally obliged to report any suspected sightings of ALB.
For more information visit http://www.forestry.gov.uk/asianlonghornbeetle.