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Exotic pest alert
An exotic beetle pest of broadleaved trees has recently established in New York and Chicago in the USA. The pest is the striking black and white Asian longhorn beetle (ALB), Anoplophora glabripennis, a member of the beetle family Cerambycidae. ALB is a native of SE Asia (China (including Taiwan), Korea and Japan) where it is a major problem on broadleaved trees, especially in China. Specimens of ALB have been intercepted in many locations dealing with imported material in North America and, as a result of a recent alert to Forestry Commission plant health inspectors, in several locations in Great Britain. As yet, there is no evidence to indicate that it has successfully attacked trees in Britain but, in view of the records of interceptions, it is vital that any finds are notified immediately to the addresses below.
BIOLOGY OF THE ASIAN LONGHORN BEETLE Depending on geographic location and average temperatures the beetle develops through a full cycle in either one or two years. The AdultAdult emergence generally takes place from May to August, but may extend to October at lower temperatures. Signs of emergence are masses of wood shavings at the entrance to the round exit hole (9-11 mm diameter) and on the ground below the tree. Beetles fly to feed in the crowns of trees and to mate. Females lay eggs singly in slits which they cut in the bark of branches, usually where they join the trunk. The symptoms of which include some resin bleeding. Females live up to 66 days and lay around 30 eggs. Eggs Egg hatch, which takes from 7 to 17 days depending on time of year and on temperature, occurs in June/July during a one year cycle and in September/October during a two year cycle. Larvae The newly hatched larvae feed under the bark, where they pass through two moults, eventually boring into the wood in the late third or fourth instar stage. Feeding continues under the bark for one more instar, by which time the larvae have grown to approximately 50 mm long. Damage to the wood increases as the larvae grow, leading to galleries within the heartwood that might be up to 10 mm in diameter and several cm long. Larvae may be present at any time, including overwinter. Pupae When fully mature, the larvae moult to the pupal stage within a well-defined pupal chamber, packed at one end with distinctive wood "shavings". This usually takes place in the spring.
THE RISK POSED BY ALB ALB is a major pest in China, Korea and Japan where it kills many species of broadleaved trees, including maples (inc. sycamore), poplars, alders, willows, cherries, apples, horse chestnut, elm, mulberry, boxelder, etc. The threat to Britain posed by the beetle has been emphasised by the establishment of populations in New York (discovered in 1996, probably present for at least three years), Chicago (discovered in July 1998, probably present since at least 1993) and in Austria (discovered in August 2001). In New York and Chicago, damage to street trees is high and a policy of felling, sanitation and quarantine is being exercised as the only viable management option.
THE RISKS TO BRITAIN The larval stages of ALB are well protected within untreated wood and, therefore, it is possible for the beetle to be carried in international trade and to emerge in the final destination. This is undoubtedly what lead to the infestations in the USA, where damaged trees in urban environments first alerted the authorities to the presence of the beetle. Analysis of climate data by scientists at the Central Science Laboratory suggests that most of England and Wales and some warmer coastal areas of Scotland are suitable for beetle establishment and breeding. The greatest risks come from presence of the beetle in packaging material associated with a very wide range of commodities from China . We can expect extensive damage to both urban and woodland/forest trees if the beetle establishes here in Britain.
BE ALERT Look for any of the following symptoms and report them immediately, providing information on damage, tree species and precise location. Pack any specimens securely in a crush-proof container ( a film canister is ideal) and fasten the top with adhesive tape: - imported wood and wooden packaging, dunnage, etc. Presence of oval "grub holes", arising from larval feeding, with diameters > 3 mm. Also presence of round adult emergence holes up to 12 mm diameter. The adult stage may also be present during the spring and early summer.
- broadleaved trees. Any of the symptoms in the illustrations, particularly the signs of late stage feeding and possible broken branches, dead branches, dead tops or completely dead trees.
Asian Longhorn Beetle continues to cause concern with the report of an outbreak in Austria in August 2001. This is the first record of it having established in Europe; Pest Risk Analysis indicates that it could establish in Great Britain, particularly the southern half of the country. We are continuing to monitor a wide range of goods imported from China (now covered by statutory import requirements) to keep this serious pest, which affects many hardwood and some fruit trees, out of this country
- CONTACT
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<><> Forest Research
Entomology Branch
Alice Holt Lodge
Wrecclesham
Farnham
Surrey GU10 4LH Tel: 01420 22255
Fax: 01420 23653 E-mail: h.evans@forestry.gsi.gov.uk | Forestry Commission
Plant Health Service
231 Corstorphine Road
Edinburgh EH12 7AT Tel: 0131 314 6414
Fax: 0131 314 6148 E-mail: plant.health@forestry.gsi.gov.uk |
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