The Asian Long-horned Beetle (ALHB) is a forest insect pest native to China and Korea that arrived in North America in the late 1990s and attacks a variety of native hardwood species. It is believed that ALHB arrived in North America in untreated wooden packing materials, such as crates, from China.

Characteristics

Adult ALHB are shiny black in colour with random white spots, long antennae banded in black and white and blueish white legs. They are large, 2-3.5 cm (.79-1.4 in) long with antennae as long as 10 cm (3.9 in). The ALHB does have wings and can fly but for only short distances because of its size and weight.

ALHB attack a large variety of both healthy and weakened deciduous trees with maples, poplar and willow being among its favourites. They also attack elm, ash, birch, horsechestnut and boxwood. Female ALHB will chew through the bark of a tree down to the cambial layer leaving a round hole approximately 1 cm (.4 in) across. The female will then back out of the hole, turn around and deposit an egg. Females can lay up to 32 eggs and will lay them anywhere on the trunk and larger branches of a tree. The larvae burrow further in the tree to feed on the phloem and xylem layers. They overwinter either in the larvae or pupal stages and emerge as adults anywhere from May to October with July being the peak period for emergence.

Distribution

The ALHB is native to China and Korea where it is considered to be a major pest in poplar plantations and causes widespread mortality among poplar, willow, elm and maple.  ALHB has been found in Ontario in the Toronto and Vaughan regions.  To date just over 27 000 trees have been removed in the Toronto and Vaughan regions in an effort to eradicate ALHB from these areas.  It has also been found in various locations in New York, Illinois and New Jersey.

Impact

ALHB attacks both healthy and stressed hardwood trees of all sizes and can kill a tree within one to two years after a heavy infestation. It is considered to be the most serious forest pest in its native range in China, particularly for poplar species. Among ALHB's favourite trees that it feeds on are poplar, maple, willow, birch, elm, ash and horsechestnut. The holes and subsequent feeding on the inner layers of the tree cause girdling and eventually kill the tree. Often sap will leak from these holes and there will be sawdust on branches and the ground from the larval feeding activity.

The variety of trees that ALHB attacks and subsequently kills, and the large range of environmental conditions it can survive, gives it the potential to alter North American forest ecosystems. Trees maintain soil structure, healthy watersheds and help clean the air of carbon dioxide and contaminants particularly in urban settings. The loss or decline of the variety of trees that ALHB attacks would limit habitat and food for many species and could impact forest and urban biodiversity. Since ALHB also attacks and kills willow species, their potential loss could also have an impact on wetland ecosystems.

The decline or elimination of hardwoods from the North American landscape will have both economic and aesthetic impacts. Many hardwoods are found in urban and rural landscapes and mature trees that are lost in these settings will be difficult to replace and often have to be replaced with less desirable, ALHB resistant specimens. The impacts in the forest product industry could be devastating for furniture, building product, and recreational product manufacturers since ALHB turn lumber that is high-grade into low-grade material generally used only for packing. The nursery trade could also feel an impact by limiting the number of tree species it can sell if ALHB can be transported on nursery stock.

Prevention

The Canadian Food Inspection Agency (CFIA) has placed an Infested Places Order for the cities of Toronto and Vaughan. This order prohibits the movement of any tree materials including nursery stock, trees, leaves, logs, lumber, wood, firewood, wood chips and bark chips from certain deciduous trees identified as hosts of the ALHB.  The ALHB has no natural controls in North America that would prevent its spread.  The latest scientific information provided by CFIA and the Canadian Forest Service, indicate that removing and destroying all susceptible hardwood trees within 200 meters of known infested trees will be sufficient to eradicate ALHB from these areas.

The CFIA along with the full cooperation of the City of Vaughan, the City of Toronto and other federal, provincial and municipal partners is implementing an aggressive campaign to control and eradicate this unwanted pest.

More information on the ALHB can be found on the agency's website www.inspection.gc.ca 

and the MNR's website http://ontariosforests.mnr.gov.on.ca/foresthealthoverview.cfm

 

 If you see the ALHB or signs of infestation, call CFIA toll-free at 1-800-442-2342

or the OMNR at 1-800-667-1940