Emerald Ash Borer

The emerald ash borer (Agrilus planipennis) is an insect that has gained a lot of notoriety due to its rapid spread across the country and devastating impact on most of our native ash trees. Emerald ash borer was first identified near Detroit during the summer of 2002.

This insect is native to Eastern Russia, Northern China, Korea and Japan. In its native habitat, emerald ash borer is held in check by parasitic wasps and birds so that populations rarely build to the point that it does extensive damage. In our country where no natural controls exist, populations of this insect have exploded such that most species of native ash have come under attack.The emerald ash borer is destroying native ash trees in Frederick County and much of the East.The emerald ash borer is a metallic green beetle that emerges from ash trees from May until July where they have two to three months to disperse, mate, and lay their eggs on ash trees before dying. The eggs hatch in about two weeks; then the grub-like larvae burrow into the tree and feed on the inner bark and sapwood of the host ash tree. The feeding activity cuts off the transport of water and nutrients inside the tree, effectively girding the tree.

Infested trees generally die in 1 to 3 growing seasons. Adult emerald ash borers can disperse about 5 to 10 miles per year. Dispersal is much further if infested firewood, mulch, or nursery stock is moved from one location to another.

Emerald ash borer was detected in Maryland in 2003 when an inspector with Maryland Department of Agriculture located tainted ash nursery stock in a nursery in Southern Price George’s County. A quarantine area was delineated in a 2-mile radius around the nursery, and efforts were made to eradicate the pest before it could spread further. These efforts delayed but did not prevent the further spread, and the quarantine was enlarged to include southern Prince George’s and Charles County.

In 2009 the state Department of Agriculture started deploying the purple prism monitoring trap throughout the state to see if EAB has spread beyond the quarantine area. Monitoring these traps confirmed that EAB had moved into Howard County in 2011. The 2012 census showed that EAB had spread into nine separate counties. The 2013 survey indicated that this serious insect pest had spread into Frederick County.

While Maryland was waging a battle with this insect within its borders, the emerald ash borer was spreading east and westward from Michigan and today it is found in 16 states, with Louisiana the latest state to be invaded.

Losing our native ash trees will impact the biodiversity of the forests and create financial impacts on landowners, the forest products industry and local and state governments. These financial impacts will significantly affect urban areas that have to deal with treatment or removal costs of ash trees.

It is estimated that the City of Baltimore has nearly 300,000 ash trees growing along right of ways. Forest landowners will also be impacted along with industries that utilize ash wood like baseball bat manufacturers, flooring, and furniture companies. Forest inventories reveal that a significant amount of the ash found in Maryland is located in our back yard in the mountainous areas between Frederick and Washington Counties.

Article by FCFCDB member

Nature Notes for 3/1/2015