What is Emerald Ash Borer?
The emerald ash borer (EAB) is an iridescent green beetle, about ½ an inch in length, originating from China. It was first identified in North America during 2002 and is thought to be accidentally introduced through the importation of wood packaging material. The larval stage of the EAB feeds exclusively underneath the bark of ash trees. The damage left in the larva’s wake kills the ash trees within three to five years after the initial infestation. Over the course of a short few years, the EAB spread to Pennsylvania as well as to 32 other states.
Why is the Emerald Ash Borer so harmful?
It's estimated that up to 100 million ash trees may have been killed by the emerald ash borer. As of 2014, ash forests in Pennsylvania were reduced by 12 percent. According to DCNR, the potential damage to the U.S. economy by 2019 may exceed $10 billion across the 33 affected states. The loss of the ash trees will also have a major ecological impact in the surrounding landscape, particularly along streams and in residential areas. Without active management, the ash population in impacted areas will be decimated.
Signs of an Emerald Ash Borer Infestation:
- Upper crown dieback (deterioration in a tree's crown or an overall reduction of tree vigor)
- Epicormic branching (shoots growing towards the tree base)
- Bark splits (bark splitting from tree)
- Bark flaking (bark peeling off)
- Tissue damage resulting from woodpecker predation
- D-shaped adult beetle exit holes in the bark
- S-shaped larval feeding galleries just below the bark
Trees vulnerable to the EAB include all North American ash species, ash cultivators, and the white fringe tree.
How to treat Emerald Ash Borer
There are three main methods of controlling the EAB. Tree removal - which reduces the available food source for larva, thus preventing the beetle from spreading outside the already infected areas. Chemical control in the form of insecticide. And biological control through the use of four different parasitoid species which feed on the larva of the emerald ash borer and are from the same native range in China.
The emerald ash borer can infest an ash tree for up to four years before there is noticeable signs of decline occurring in a tree. If you have trees in question, it is recommended to contact your local tree service professional to receive a complete tree evaluation to safely address any issues that will require deliberate care. For further state information, visit https://www.dcnr.pa.gov.