Presence of the Citrus Longhorn Beetle in UK

An invasive non-native insect which could harm woodland areas and garden plants in the UK has been identified. The Citrus Longhorn Beetle (Anoplophora chinensis) has been brought in on Acer plants (Acer palmatum or 'Japanese Maple') imported from China via the Netherlands and distributed by mail order. This pest is not established in Great Britain but there have been several recent findings in different parts the country.

Although the beetle is known to have been introduced in Acers, it can affect a wide range of trees or shrubs, such as oak, beech, ash, maple, apple, pear, willow, hibiscus, horse chestnut, hornbeam, hazel, birch, mulberry and rose.

Citrus Longhorn beetles develop inside plant stems and tree trunks, taking between one and three years to emerge, and are therefore difficult to detect.

Prior to emergence, there are no obvious symptoms of infestation or the presence of a larva or pupa within a plant or tree. However, large (6-11 mm) exit holes are left by the emerging adults in the stem. These exit holes may be just above ground level, but can also be just below ground level and as such are not visible. Other symptoms can include:

* Scraped sections of bark

* Chewed leaves and damage to the petioles by adults

* T-shaped egg slits in bark

* Saw-dust like 'droppings' or wood pulp around holes and larval tunnels in the wood under loose or thin bark.

Examination of the ground at the base of the shrub or tree for signs of wood shavings provides a rapid method of detecting activity of late stage larvae.

These large black beetles grow to between 21-37mm long and have distinct white markings and long "horns" or antennae. The antennae are longer than the body and are black with white bands. It could be found on a wide range of trees or shrubs.

If you see one of these distinctive beetles, please isolate it in a sealed container and contact your local Plant Health and Seeds Inspector (PHSI) details of whom can be found on the Defra website - http://www.defra.gov.uk/planth/senior.htm or telephone 01904 455174. The PHSI should also be notified if there is other evidence of Citrus Longhorn beetle infestation.

Further information about the Citrus Longhorn Beetle is available at http://www.defra.gov.uk/planth/pestnote/2006/citlong.pdf

All suspect alien invertebrate plant pests must be reported to the local Defra Plant Health and Seeds Inspectorate office or the PHSI HQ, York (Tel.: 01904 455174, Fax: 01904 455197).

Public enquiries 08459 335577;