Emerald Ash Borer

Emerald ash borer, Agrilus planipennis, is a newly introduced species (found in 2002) from Asia and populations have been found in southern Michigan, Ohio, and Indiana (USDA - Forest Service 2004). Maryland and Virginia have also reportedinfested tree nurseries. Larvae feed on the phloem and sapwood of ash species (Fraxinus spp.) girdling and killing the trees. In America, white ash (F. americana), green ash (F. pennsylvanica), and black ash (F. nigra) have been infested as well as ornamental varities of ash.

The emerald ash borer usually has a one year life cycle. Adults emerge in early summer. The adult beetles usually live for about three weeks, during which they are very active during warm, sunny days (BROKEN-LINK USDA - Forest Service 2002). Adult feed upon ash leaves and lay their eggs in the bark crevices of ash trees. Once the eggs hatch, the larvae bore into the cambium layer and begin making winding S-shaped galleries. The larvae overwinter inside the tree and pupation begins in late spring. The new adults emerge in early summer, leaving a clear cut, D-shaped exit hole (BROKEN-LINK USDA - Forest Service 2002).

Adults are large, slender beetles (7-14 mm in length) (BROKEN-LINK USDA - Forest Service 2002). Adult bodies are green to bronze in color. The wing covers are noticably metallic green in color. The larvae are 26-32 mm in length, cream colored, and dorsa-ventrally flattened.

Typical infestation symptoms include the presence of D-shaped exit holes, vertical splitting of the bark, and epicormal sprouts (BROKEN-LINK USDA - Forest Service 2002). Crown dieback usually occurs after two years of infestation. Trees often die after 3-4 years of infestation.

Although ash species do not dominate the southern Appalachians as they do in other eastern forest, they still comprise a significant proportion of the forest canopy. Emerald ash borer has the potential to severely reduce the occurence of ash throughout the southern Appalachians, altered the ecosystem and

reducing the forest canopy biodiversity. For more information on emerald ash borer click here.