Emerald Ash Borer: Learn about about this "invisible" New Jersey ash tree killer

Updated: May 3

A non-native pest to New Jersey, Emerald Ash Borer infests and kills all types of ash trees present in North America. It was first spotted in the U.S. in Michigan in 2002. It has since killed hundreds of millions of trees in 28 states and two Canadian provinces. Considering 24% of New Jersey’s forests have ash trees, with the largest concentration in northwestern portion, the Emerald Ash Borer poses a real threat to the wooded regions of this state.


Identification and life cycle of the Emerald Ash Borer

Emerald Ash Borer
The Emerald Ash Borer poses a real threat to New Jersey neighborhoods.

The adult Emerald Ash Borer is about ½-inch long and 1/8-inch wide and is a metallic green, hence the “Emerald” in its name. The insect’s abdomen is a metallic coppery red.


Adults emerge this time of year in May/early June and make a D-shaped exit hole in whatever branch or trunk it had been in. Female adults feed on the edges of the ash leaf and afterward deposit eggs in crevices in or under bark. Once matured, the larvae emerge from the eggs and burrow under the bark to feed on the water and nutrient transporting layer of the tree, thereby damaging the tree. The larvae remain there until they become adults in April or May.


What to look for: Signs of Emerald Ash Borer damage

Emerald Ash Borer tree damage
Inside an ash tree that has been infested with the Emerald Ash Borer.

What makes spotting the Emerald Ash Borer so difficult at first is that they infest a tree starting at the top, making it nearly impossible to see the insects or spot their exit holes. Infested trees will live just three to four years after being infested. Other signs of an infestation include:

  • Increased woodpecker activity as they feed on the insects

  • As the infestation in the tree grows from year to year, you may see the crown of the tree die

  • Bark splitting and new branches sprouting along the trunk




What To Do If You Find Signs of Emerald Ash Borer


Call the USDA Emerald Ash Borer Hotline at 1-866-322-4512 or your local USDA Animal and Plant Health Inspection Service (APHIS) office if you suspect Emerald Ash Borer is on your property. Also call a Certified Arborist in New Jersey right away.

Concerned about your tree health? We can help. Plant Solutions NJ has certified arborists on staff to deal with the threat that Emerald Ash Borer poses to your property and community.




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