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Emerald Ash Borer Recommendations and FAQs

Q: What is the Emerald Ash Borer (EAB) and what does it do?
This Asian beetle, discovered in 2002 in southeastern Michigan and Windsor, Ontario, infests and kills North American ash species (Fraxinus sp.) including green, white, black and blue ash, and their cultivars.

The larval stage of EAB feeds under the bark of trees, cutting off the flow of water and nutrients. Infested trees gradually die over a 2-4 year period.

Q: What does EAB look like?
EAB adults are dark metallic green in color, with a coppery red or purple abdomen under the wings. The insect is approximately ½ inch long and 1/8 inch wide. Adults may be present from late May to September, or later, but are typically most common in June and July.

Larvae are creamy white in color and are found under the bark, so are not obvious, but their expanding S-shaped galleries (tunnels) may be seen if the bark is removed. Larvae themselves are hard to see.

When adult beetles emerge from the tree, they leave distinctive D-shaped (half-moon shaped) exit holes in the outer bark of branches and the trunk. Their presence typically goes undetected until trees show symptoms of being infested.

Q: Where did it come from?
The native range of the EAB is eastern Russia, northern China, Japan and Korea.

Q: When was EAB first discovered in North America?
EAB was first identified in southeast Michigan and Windsor, Ontario in 2002. It likely arrived several years earlier.

Q: How did it get to North America?
We don't know exactly, but it most likely traveled in ash wood used for stabilizing cargo in ships or for packing consumer products.

Q: How does EAB spread?
EAB is not a particularly strong flier. Adults typically fly less than ½ mile from their emergence tree. Most long-distance movement of EAB has been directly traced to ash firewood or ash nursery stock. Other untreated ash wood, wood chips greater than one inch, and ash product movement (logs, lumber, pallets, etc) generally present lesser risks. Wood chips less than one inch or mulch are considered to pose little risk of movement. New York currently has a regulation restricting the movement of firewood to protect our forests from invasive pests.

Q: How do you identify ash trees?
Ash trees can be identified by the following:

  • Branches, leaves and buds are directly opposite from one another rather than staggered
  • Each leaf is compound, made up of 5-11 leaflets
  • Bark has a distinct patterns of diamond-shaped ridges, although the bark on smaller ash trees is often smoother

Q: Why should New York care? How serious is this?

EAB infestations are always fatal to ash trees. Infested trees will decline from the top down and will be dead in approximately 2 to 4 years, even if the trees were healthy before being attacked by EAB.

Ash is a very common street tree in many New York communities. It was widely planted to replace native elms lost to Dutch elm disease. In Michigan, the first infested state in the U.S., 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.

Ash is also a common and important 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. Ash is a commercially-valuable species, and is used for baseball bats, flooring, furniture, lumber, and pallet manufacture. Black ash is also prized by Native American tribes, including the Akwesasne, for traditional basket making. The estimated annual contribution of forest-based manufacturing and forest related recreation and tourism to the New York State economy is over $9 billion.

Q: What is being done about EAB?
There is a national effort to limit the spread and impact of EAB. A national plan, coordinated by the U.S. Department of Agriculture (USDA), Animal Plant Health Inspection Service (APHIS), helps guide what federal, state and local officials must do to manage this insect. Infested areas are quarantined, which means that selected materials such as firewood, ash nursery stock and ash logs may not be moved out of infested areas. Many states are educating the public on the dangers of moving firewood, the primary way EAB and many other invasive pests and diseases of trees are spreading.

Q: What is being done in New York?
The State has been taking several actions over the past several years. The New York State Department of Environmental Conservation (DEC) and the NYS Department of Agriculture and Markets, are currently leading efforts to detect, prepare for and regulate the movement of EAB into and within New York. DEC is conducting detection surveys in areas deemed high risk for EAB introduction. For the past several years DEC has surveyed for EAB using a variety of methods, including baited traps and established "trap trees" in an attempt to determine if EAB is present in our forests.

In June 2008, a regulation was enacted to restrict the movement of firewood to within 50 miles of its source in order to protect trees and forests in the state from EAB and other invasive insects and diseases.

Q: What are those purple, wedge-shaped things hanging in the trees?

They are emerald ash borer traps, also known as "purple prism" traps. The traps are used for early detection and boundary marking of EAB infestations. Unfortunately, they don't catch enough beetles to control populations, but their use in early detection is crucial, as the sooner an infestation is found the easier it is to manage.

Hung high in ash tree branches, the traps contain a lure which smells like a stressed ash tree. The lure, and the trap's purple color, draw in the beetles, which get stuck in the very sticky glue that coats the outside of the trap. When the traps are inspected throughout the summer, any EABs, or look-alikes, are collected and sent to a lab for identification.

In 2010, all of the new infestations were first detected via the purple traps. More than 8,000 traps were set in New York State in 2010, primarily within a 100-mile radius of known EAB infestations and in high risk areas, such as campgrounds. Additional traps were hung for research purposes.

Don't worry if you have purple prism traps on or near your property. It doesn't necessarily mean that your area is under attack by EAB. It's just a precaution. But if you do suspect you might have EAB, call the hotline number at 1-866-640-0652.

For Property Owners

Q: Is there anything I can do now to protect the ash trees in my yard from EAB?
There are systemic insecticides on the market, but their effectiveness varies greatly and they can be expensive. The decision to treat individual trees is a personal preference, but consumers should educate themselves and use caution when purchasing products that claim to protect trees against EAB. See the Treatment Information Offsite Link in the right column of this page for more information about treating trees against EAB.

Q: Is ash still a viable choice when considering what to plant in my yard?
In general, having a diversity of species in your yard, on your street or in your community is your best defense against all tree health problems. If ash comprises 10 percent or more of the tree species in your local area, it would be best to choose an alternative.

Q: What can I do to help?
Stop. Learn. Plan. Then act. Acting without understanding the specific threat to your trees, regulations and quarantines, and your options, could cause the unnecessary loss of treasured shade trees, or loss of substantial income from your woodlot.

Do not move firewood. Purchase or cut firewood from the same general location where you plan to use it. When camping or at a cabin, do not take any leftover firewood home with you. Educate yourself on how to recognize signs and symptoms of EAB. Some excellent sources of online information are listed below.

Report possible sightings of EAB by calling DEC at 866-640-0652 or fill out a survey form (PDF 173 KB).

For Municipalities

Q: How should my community plan for EAB?
Municipalities need to be prepared for the possibility of the emerald ash borer (EAB) infesting community ash trees. Check out the Community Preparedness Plan Workbook (PDF, 200 KB) from Cornell University Cooperative Extension.

For the Wood Products Industry

Q: Where can I find information on markets for ash timber products?

Q: Where can I find more information on ash utilization?
For information on ash utilization projects, visit (leaves DEC website)

Q: Where can I get technical assistance?
For wood products industry technical assistance, contact the Forest Utilization Program at (518) 402-9425.

For Rural Forest Owners

Q. How do I prepare for EAB?

Q. How do I market Ash Trees?

Q. Where can I get help?

For Educators

The following links lead off the DEC website. By clicking on them, you will leave the DEC website.