Emerald Ash Borer: What Can You Do?

New discoveries of emerald ash borer in NY State are now confirmed in 7 counties. PA adds 31 counties to the emerald ash borer quarantine. What can you do?

The most important thing to understand is that all the ash trees in the northeast, or for that matter all of North America, are threatened by the EAB. It’s not a question of it will arrive in your community, but when. The cost to forest and woodlot owners will be significant through lost timber revenue, but before liquidating your ash resources we recommend developing a management plan that considers the impact of potential ash harvesting activity on the longer term health and regeneration of more valuable species in your stand such as oak, cherry, and hard maple. By far the greatest economic impact of EAB will be to homeowners and communities who must manage urban forests. Liability issues with dead and dying ash trees demand the fast removal of infested trees before they are a threat to public health. Tree removal or treatment costs can be significant and can occur over a short time period. Planning is the key to mitigating these costs and it is imperative that all communities in the northeast, infested or not, begin the planning process now.

The first question to ask is “How many ash trees are we responsible for?” Once communities and homeowners know this information they can begin the decision making process by calculating the costs of different options such as removal and replacement as well as possible treatment with systemic insecticides. It is important to include in pesticide cost estimates the fact that insecticide treatments last for only 1 to 2 years and that the EAB may persist in an area killing trees for perhaps a decade, so multiple treatments will be necessary. It is also a waste of money to try to protect your ash unless the EAB has been documented within 10 to 15 miles. In addition, although the effectiveness of some insecticides is high, the ability of large old trees to spread it evenly through the crown may be hindered by a vascular system that has been compromised through time by broken branches, pruning scars, or heart rot. If the insecticide does not reach a part of the tree crown it will be killed by EAB and the aesthetic value of the tree may be diminished significantly. We recommend anyone considering the use of insecticides to consult with a certified arborist.

There are many other things communities can do to prepare for EAB arrival such as the creation of marshalling yards to deal with the volume of dead ash material that needs to be disposed of, the purchase and maintenance of machinery necessary to chip or grind ash, and finding a use for the chipped material. Many of these operations would be less expensive if municipalities were to work together. The important thing to realize is that everyone needs time to plan ahead to minimize the economic impact of EAB and the time to begin is now.

Finally, everyone needs to minimize the movement of firewood so the spread of EAB can be slowed down. The movement of firewood is the reason EAB has spread so rapidly. We must take ownership of this issue and help our neighbors to understand that the movement of untreated firewood threatens the health of our forests from not only EAB, but any new invaders that may appear. In New York it is now the law that no untreated firewood can enter the state and firewood produced within the state cannot be moved more than 50 miles. As NYSDEC Commissioner Grannis has stated “We understand that people aren’t being intentionally reckless when they use wood from their own lot or bring it with them across the state to go camping, but everyone needs to understand the potentially devastating effects on our forests and our communities from the bugs that infest untreated firewood.”

For information on how to plan and react to the discovery of EAB in your community, review the article on EAB in the Fall 2009 issue of Small Farms Quarterly.  www.smallfarms.cornell.edu/pages/quarterly/archive/fall09.cfm


New York State Residents
For more information on the EAB and issues concerning its impact on communities contact your local Cornell Cooperative Extension office.
Pennsylvania Residents
Pennsylvania, if you suspect you may have EAB in your ash trees, call 1-866-253-7189

Marc Whitmore

Marc Whitmore is an Extension Associate in the Natural Resources Department at Cornell University. He may be reached at 607-280-4064 or mcw42@cornell.edu


  1. Avatar of Marjorie Marjorie on September 25, 2012 at 1:51 pm

    Thank you very much for answering our quietson about the purple triangluar boxes hanging from trees in our area. My husband & I were riding around yesterday after we ate and saw 4 of these boxes hanging beside different country roads. We tried to guess what they were but we weren’t even close to the correct answer.

  2. Avatar of Henry Larry Henry Larry on April 3, 2024 at 6:16 am

    Understanding the imminent threat of Emerald Ash Borer is crucial for both homeowners and communities. Planning ahead and taking proactive measures such as minimizing firewood movement and consulting with experts are vital steps to mitigate its economic impact.
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