USDA - APHIS - Plant Health, Plant Protection and Quarantine

Emerald Ash Borer

The Emerald Ash Borer (EAB) Program works to prevent the spread of EAB and mitigate the damage it causes to America’s ash trees. The native range of the emerald ash borer (EAB) includes China, Mongolia, North Korea, South Korea, Japan, Taiwan, and the Russian Far East. The EAB was unknown in North America until its discovery in southeast Michigan in 2002. Today, EAB infestations have been detected in 18 states; Connecticut, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Wisconsin.

APHIS works with State cooperators to detect, control and prevent the human spread of the emerald ash borer beetle. Strategies to manage the pest focus on survey and regulatory activities to slow its spread, and public awareness campaigns to garner program support and compliance. APHIS continues to identify effective tools to manage and control EAB populations. Early in the program, APHIS and the Forest Service (FS) initiated a search for potential biological control agents in The People’s Republic of China. Three potential biological control agents were identified—Spathius agrili, Tetrastichus planipennisi and Oobius agrili. Since 2007, ongoing releases of these stingless wasps show some promise as a long-term management strategy. For more information about the EAB Biological Control Program: Emerald Ash Borer Biological Control Release and Recovery Guidelines. Efforts to find additional biological control agents are ongoing.

The EAB is an enormous threat to our urban, suburban and rural forests. EAB kills stressed and healthy trees and is so aggressive that ash trees may die within two or three years after they become infested.
Ash trees are as important ecologically in the forests of the northeastern United States as they are economically. Ash trees fill gaps in the forest and are highly desirable for urban tree planting. Ash wood is valued for flooring, furniture, sports equipment (e.g., baseball bats, hockey sticks, oars), tool handles, and supplies for dairies, poultry operations and beekeepers. Ash trees and wood are also significant to Native American cultures for traditional crafts and ceremonies.
In ash trees, EAB larvae feed under the bark and it is this activity that eventually kill the trees. EAB adults mate shortly after emergence. Each female can lay 60-90 eggs in their lifetime and eggs typically hatch in 7-10 days. Minute larvae bore through the bark and feed on the phloem. Larvae continue development into early fall. In the spring, EAB pupae start to transform into adults and in 1 to 2 weeks a new generation of EAB adult beetles emerge through D-shaped exit holes. Adults prefer clear, calm days and the warm, sunny sides of the trees. Adult EAB live two to three weeks.

In the United States only ash trees (Fraxinus spp.) are at risk for EAB. Ash trees are widespread in the United States and all 16 native ash species are susceptible to attack. Ash trees with low population densities of EAB often have few or no external symptoms of infestation. Symptoms of an infestation might include any or all of the following: dead branches near the top of a tree, wild leafy shoots growing out from the trunk, bark splits exposing larval galleries, woodpecker activity and D-shaped exit holes; see photo gallery for images.