Fairmaire, 1888 (Emerald Ash Borer )
Adult Description: The Emerald Ash Borer (Agrilus planipennis) are uniformly bright metallic emerald green, with the elytra usually appearing somewhat duller and slightly darker
green. The overall greenish coloration may also have variable amounts of brassy, coppery or reddish reflections. A few rare specimens of Emerald Ash Borer are entirely coppery-red, blue-green, or green with blue elytra. Length: 10.0-13.0 mm. Emerald Ash Borer is somewhat larger in size and more brightly metallic green than most other U.S. Agrilus species.
Larva Description: Emerald ash borer larvae are white and slightly flattened, with a pair of brown pincher-like appendages on the last abdominal segment. Their size varies as they feed under the bark of the ash tree's tissues. Full grown larvae average 1.5 inches in length. They wind back and forth as they feed, creating characteristic S-shaped patterns called galleries under the bark.
Host Plant: Ash trees (Fraxinus);
History: Emerald Ash Borer was accidentally introduced into southeastern Michigan sometime in the 1990's in wood packing material imported from eastern Asia.
Biology: Larvae will feed under the bark for one or two years (longer in healthy trees), and can survive in green wood, such as firewood, even if the tree is no longer standing.
Ecological Threat: Larvae feed in the phloem and outer sapwood of Ash trees producing galleries that eventually girdle and kill the tree. This invasive pest has had a devastating impact on communities that now face significant tree removal costs associated with dead or dying ash trees that pose a threat to public safety. Other repercussions include decreased property value, losses in the long-term supply of ash wood, decreased air quality, increased electricity use during hot weather, and negative impacts on Native American cultures that use ash wood for traditional crafts and ceremonies. In addition, there are other detrimental impacts on wildlife and natural ecosystems. States which become infested could lose billions of dollars in forest products and quarantines imposed by state and federal agencies and may have serious consequences for plant and wood products industries. Severe damage may also occur within the tourist industry with the loss of tree cover in campgrounds.
US Habitat: Emerald Ash Borer targets Ash trees (Fraxinus sp.) in landscape, horticultural and forest settings. Also known to attack white fringetrees (Chionanthus virginicus).
Resembles: Native Agrilus sp.
Management: Insecticide: Treat with an insecticide only if the tree is apparently healthy or less than 40 percent of the crown has died, discolored, or has sparse foliage. Research has shown that trees with more than 40-50 percent crown dieback do not benefit from treatment. Treatment requires a long-term commitment. Contact a certified arborist (www.waa-isa.org/arborists/search.asp) to evaluate your treatment options.
Last Updated: 2020-07-07 by Hans Landel - Lady Bird Johnson Wildflower Center