The emerald ash borer is here in Massachusetts, but not to the surprise of tree care professionals. This is a very destructive insect pest that is killing ash trees everywhere it is found. It will only kill ash trees, any variety of ash.

This invasive pest was first discovered in Michigan in 2002, and has since then spread to a total of 18 states in the northeast. It was discovered in Connecticut earlier this year, and the Massachusetts find was made August 30 in a specially designed purple EAB trap by a staffperson with the Dept. of Conservation & Recreation in Dalton, out in the Berkshires. The pest was found in eastern NY last year, so Mass. arborists knew it was only a matter of time.

What is the significance of the emerald ash borer? It will kill an ash tree in as little as 3-4 years. It is difficult to find a newly infested tree, as they prefer to start higher up in the tree’s canopy, and their exit holes are only about a quarter inch. By the time the pest becomes noticeable on the tree, it is likely already dying. But this would serve to be a warning that it is in your neighborhood, and if you have valuable ash trees, it would be time to begin treating them. Unlike the Asian Longhorned Beetle, the is no federal program to eradicate this pest, as eradication is not a practical means of stopping this pest. It will likely continue to spread and kill ash trees until there are none left unfortunately, making treatment the only viable option in the maintained landscape.

The bright green adult beetles can be found from June to August, and they will feed lightly on the ash tree’s foliage. Larvae will grow and feed in the phloem from July to November. Their mortality is not affected by cold, but woodpeckers do like to feed on them at this time through the winter. the adult will then emerge in June-July.

If you have a valuable ash in your landscape, watch the news of this pest- it doesn’t exist in the eastern part of the state yet, but when it does move in, you may want to begin protective treatments. Your Mayer Tree Service arborist can help you with that decision making process. If you would like more information about the emerald ash borer, visit