The emerald ash borer (EAB) (Agrilus planipennis) is a wood-boring beetle from Asia that feeds on all native ash trees (Fraxinus sp.) in New York State. It was accidentally transported in infested crates and pallets to the United States where a lack of natural controls such as predators and disease allowed the population to grow rapidly. Since its introduction, it has killed millions of ash trees and has cost billions of dollars in damage and loss.
Description
EAB has four life stages: adult, egg, larva, and pupa. The adult beetles are small, roughly 3/8 to 5/8 of an inch long, with metallic-green wing covers and coppery red or purple abdomens. The larvae are off-white, worm-like, and about one inch long with bell-shaped segments.
EAB females lay their eggs on the bark of ash trees. After hatching, larvae chew their way in and begin feeding on the living tissue between the bark and sapwood, creating S-shaped galleries. After 1-2 years of feeding in the tree, the larvae move to the outer bark to pupate. EAB overwinter as pupas and start emerging in late May, leaving behind distinctive D-shaped exit holes in the bark. Adults can be seen through early September, but are most abundant in June and July.
Signs of Infestation
An ash tree infested with EAB may show the following signs:
- "blonding" of the trunk due to woodpeckers pecking off outer bark in search of the larvae (the light inner bark will turn gray over time);
- tree canopy dieback, yellowing, and browning of leaves;
- distinctive D-shaped exit holes in the bark; and
- S-shaped galleries under the bark, often seen when the tree's bark splits or falls off.
How EAB Spreads
Most long-distance movement of EAB has been directly traced to ash firewood or ash nursery stock. Other untreated ash products (wood chips, mulch, lumber, pallets, etc.) generally present a lesser risk of spreading EAB. Adult EABs typically fly less than a ½ mile from their emergence tree, so their natural rate of spread is of lesser concern than human-caused spread.
Distribution and Habitat
EAB was first discovered in New York State in 2009 and has been confirmed in all New York counties except: Hamilton, and Lewis.
All of New York State’s native ash (white, green, and black) are at risk from EAB.
Environmental Impacts
Once infested with EAB, most ash trees die within 2-4 years. Ash was once a commonly planted street tree in many New York communities and was widely planted to replace native elms lost to Dutch elm disease. However, many ash street trees have been impacted by EAB. In Michigan, the first state in the U.S. infested with EAB, the greatest economic impact has been on communities faced with removal of thousands of dead ash on streets and in yards. Many of these dead trees pose significant public safety hazards and liability problems for municipalities and landowners.
Historically, ash has been a common and valuable forest species:
- Ash seeds are a food source for birds and mammals.
- Ash species (white, green and black) comprise almost 8% of all trees in NY State.
- Black ash is prized by Indigenous peoples, including the Haudenosaunee, for traditional basket making.
- Ash is a commercially valuable species, used for baseball bats, flooring, furniture, and lumber.
Regulations
New York has a regulation to restrict the movement of firewood of any tree species to within 50 miles of its source (e.g. firewood processing center) or origin (where it was grown) regardless of tree species.
EAB is listed as a prohibited invasive species by 6 NYCRR Part 575. Under this regulation, no person shall sell, import, purchase, transport, introduce or propagate, or have the intent to take any of these actions on the regulated species, unless issued a permit by DEC for research, education, or other approved activity.
Management
While DEC is still collecting new EAB location information, we are not actively managing infestations. However, DEC is cooperating in efforts to identify potentially resistant "lingering ash" trees in areas thoroughly infested with EAB, and to conserve ash seed for future restoration efforts. Additionally, landowners may consider treating their ash trees. View the Insecticide Options for Protecting Ash Trees from Emerald Ash Borer (PDF).
If Your Tree Has EAB
If you confirm your tree is infested with EAB, you do not have to take it down unless the tree could pose a hazard by falling (check for nearby structures, roads, etc.). DEC can confirm if the signs of tree damage are from EAB and provide tree removal information. However there are no DEC programs to assist landowners with tree removal. Visit our tips for selecting an arborist or tree service for guidance on tree removal.
How You Can Help
How to Report a New Infestation Location
If you think you have found EAB and are in Essex, Hamilton, or Lewis county:
- Take photos of the insect and/or signs of damage.
- Email photos and location information to us at [email protected].
- You may also call DEC's Forest Health Information line at 1-866-640-0652
Additional Resources
- USDA APHIS EAB webpage – U. S. Department of Agriculture, Animal and Plant Health Inspection Service
- Don’t Move Firewood – help protect our forests from invasive insects and diseases
- Buy it Where you Burn it Poster, English (8.5” x 11”)
- Buy it Where you Burn it Poster, Spanish (8.5” x 11”)
- Monitoring and Managing Ash (MaMa) – a citizen science-driven program for conservation and mitigation, including reporting lingering ash trees
