emerald ash borer

Emerald ash borer (Agrilus planipennis). Photo: David Cappaert, Bugwood.org

Updated: May 12, 2021

Key points

  • Emerald Ash Borer (EAB) is a serious threat to Maryland ash trees. It has killed many millions of ash trees across the Mid-West and Eastern U.S.

  • This invasive pest is well-established in Maryland including the Eastern Shore. It was first introduced into Prince Georges County in 2003 and was confirmed to be infesting ash trees on the Eastern Shore in 2015. 

  • The EAB is an invasive pest from Asia that feeds on and kills ash trees. 

  • EAB will kill even large ash trees within three years after infestation. 

  • Ash trees are one of the most common and important landscaping trees used in Maryland and are common in western Maryland forests.

  • Ash wood is used for all traditional applications of hardwood from flooring and cabinets to baseball bats. 

emerald ash borer damage

Damage to young ash trees infested with EAB. Photo: David Cappaert, Bugwood.org

EAB detection

emerald ash borer woodpecker damage on ash tree

Woodpecker activity resulting in 'blonding' on ash tree branches. Photo: Jim Tresouthick, Village of Homewood, Bugwood.org

  • The presence of the emerald ash borer typically goes undetected until trees show symptoms of being infested, usually, the upper third of a tree will thin and then die back. This is usually followed by a large number of shoots or branches arising below the dead portions of the trunk.
  • Woodpecker activity can be an indication that an ash tree is infested with EAB larvae. 
  • Other symptoms of infestation include small D-shaped exit holes in the bark where adults have emerged, vertical splits in the bark, and distinct serpentine-shaped tunnels beneath the bark in the cambium, where larvae effectively stop food and water movement in the tree, starving it to death. 
  • Adult beetles begin flying in the spring about the time that black locust trees are blooming.
emerald ash borer exit hole

D-shaped exit hole. Photo: Kenneth R. Law, USDA APHIS PPQ, Bugwood.org

Management

emerald ash borer larva

EAB larva and galleries made underneath bark. Photo: Eric R. Day, Virginia Polytechnic Institute and State University, Bugwood.org   

emerald ash borer adult next to a coin

Emerald ash borer adult in tunnel. Photo: Eric R. Day, Virginia Polytechnic Institute and State University, Bugwood.org                        

To help stop this damaging beetle, homeowners and citizens who live in and travel through known infested areas can help. 

  • Don’t move firewood – buy it where you burn it.  Hauling firewood is the most common way for damaging plant pests to be moved from one area to another.
  • Don’t plant ash trees.  As EAB is expanding its range in Maryland, diversified plantings of alternative tree species are recommended for residential landscaping.
  • EAB is no longer under federal quarantine regulations, as of January 14, 2021.
  • The Maryland Department of Agriculture (MDA) confirmed the presence of the invasive, highly destructive emerald ash borer (EAB) beetle on the Eastern Shore in June 2015.
  • As of July 31, 2015, the Maryland Department of Agriculture rescinded the statewide quarantine prohibiting the movement of hardwood from the western to the eastern shore.
  • Dead trees located in yards, near buildings, or are street trees, will likely become hazardous trees and should be removed immediately by a reputable tree company. Ash trees become very brittle when they die and tree companies will not climb them for removal if they have been dead for more than 6 months. Depending on the situation a crane may be needed thus increasing the cost.