Emerald Ash Borer (Agrilus planipennis)

Emerald Ash Borer. © David Cappaert,Michigan State University, Bugwood.org

The emerald ash borer (EAB) is a species of beetle in the buprestidae family that is native to eastern Asia. It first arrived in North America in overseas shipping containers. It was first detected in Ontario in 2002 in the City of Windsor, and has since spread to other parts of the province. The EAB preys on ash trees (Fraxinus species) and is a major concern for North American ash populations.

The adult EAB is shiny metallic green in color and about 20 mm long. It feeds on ash tree foliage. Females lay their eggs within cracks in the bark of ash trees between early May and mid June. The larvae are about 26 – 32 mm long and creamy white in color. It is the larvae that kill the tree by burrowing into the trunk and feeding on the cambium and nearby tissues. The tunnels created by the larvae eventually kill the tree by disrupting its vascular system. The tree may take a few years to die after it has been infested. It is estimated that millions of ash trees in North America have already been killed by EAB.

The rapid spread of EAB has been mostly a result of human activities such as the movement of firewood and nursery stock that is infested with the insect. As such, movement and treatment of ash materials is now regulated in many areas of the province. The signs that a tree may be infested with EAB include new shoots growing from the trunk or lower branches, S-shaped tunnels underneath the bark filled with fine sawdust, small D-shaped emergence holes in the bark, the thinning of the crown, and presence of adult beetles feeding on the foliage. Sightings of the beetle or suspected infested ash trees should be reported to appropriate local authorities or the Canadian Food Inspection Agency.


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