David Cappaert, Michigan State University

Class: Insecta

Order: Coleoptera

Family: Buprestidae

Synonym(s):

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.

The dorsal surface of the abdomen is bright coppery-red. This may only be visible if the elytra and wings are raised. This is the only Agrilus species found in North America in which the dorsal surface of the abdomen bright metallic red. This may be the simplest diagnostic character for separating Emerald Ash Borer from all other Agrilus species in North America. The dorsum of the abdomen is normally black, green or blue on all other North American species of Agrilus.

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);
White fringetree (Chionanthus virginicus)

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.

Humans unknowingly contribute to the artificial spread of the Emerald Ash Borer. The movement of common ash tree products, such as firewood, nursery stock, green lumber, branches, logs, and chips, has been a primary means of advancing the beetle's spread.

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).

Distribution

Native Origin: Asia

US States: (2020) AL, AR, CO, CT, DE, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NE, NH, NJ, NY, OH, OK, PA, RI, SC, SD, TN, TX, VA, VT, WI, WV

Also found in at least 5 Canadian provinces (as of May 2020).

Texas: Discovered in a trap in NE Texas in 2016. Adults found in Bowie, Cass, and Marion Counties, infestations in Denton, Harrison and Tarrant Counties (June 2020).

If you believe you have found an emerald ash borer, please report this species immediately.

Resembles: Native Agrilus sp.
See description above for information on how to distinguish EAB from native species.

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.

Remove and Replace: This is an option for ash trees in all stages of health. Contact a certified arborist to remove trees from your yard and to appropriately process wood to prevent additional spread of Emerald Ash Borer. Replace trees with a non-ash species suitable to your site. Trees larger than 10 inches diameter produce more Emerald Ash Borer and should be considered a priority for removal.

Do Nothing: Observations in states where Emerald Ash Borer has been present for several years show that all ash trees are susceptible to infestation and mortality. If you take this option, expect your tree to become infested and die.

Text References

Wisconsin's Emerald Ash Borer Information Source. 2010. What does EAB Look Like> Accessed 18 Nov. 2010:http://www.emeraldashborer.wi.gov/article.jsp?topicid=15

USDA-APHIS. 2010. Plant Health: Emerald Ash Borer. Accessed 18 Nov. 2010: http://www.aphis.usda.gov/plant_health/plant_pest_info/emerald_ash_b/background.shtml.

Data Source

www.emeraldashborer.info
U.S. Forest Service - Forest Health Protection
Texas A&M University Forest Service EAB site
EAB attacks white fringetrees

Last Updated: 2020-07-07 by Hans Landel - Lady Bird Johnson Wildflower Center