Emerald Ash Borer

Westport, CT Tree Warden, Bruce Lindsay, would like to advise the public about the presence of Emerald Ash Borer and its effects on our ash tree Population in the community.  The ash tree is a native hardwood deciduous tree present throughout Connecticut.  Most common and abundant species are green ash and white ash.  Ash tree wood makes for great firewood, baseball bats and furniture and has been in Yankee life for decades as a commonly available and useful timber tree. The ash tree was popular to plant and maintain along streets or parks because of its useful and adaptable urban tolerances and resistance to numerous environmental stressors. The Town of Westport’s ash tree cover town wide constitutes about 1-3% of all trees in the entire town forest, slightly less on town roads and parks.  In town’s north of Westport, ash populations may rise as high as 19% of the forested cover.

Image 1: ASH TREE AT LONGSHORE CLUB PARK

Ash at Longshore

The Emerald Ash Borer or (EAB) is a non-native beetle which made its way from China to Michigan. First discovered in Detroit in 2002 and since has spread east to Connecticut, New England and now is fully verified in 35 states and 5 Canadian Provinces. By most accounts the introduction of EAB occurred through shipping containers in green pallet wood from China. Recent campaigns by the US forest service have instructed people to minimize the movement of firewood, which has become a large contribution to EAB’s spread. www.dontmovefirewood.org.  EAB will destroy an ash tree in 3-5 years and continue to infest and re-infest an ash tree until it collapses and dies while moving on to new hosts as the lifecycle continues.

In 2012, the Emerald Ash Borer was first discovered in Prospect, Connecticut and has quickly spread to all 8 counties. EAB adults lay eggs on the bark of mature ash trees. The eggs hatch into larvae and rapidly burrow into the bark of the tree and begin to feed on the inner cambium layer. As the larvae grow they feed on the tree’s tissue forming ‘galleries’ within the phloem layer of the tree.

Image 2: BORER GALLERIES IN AN INFESTED ASH TREE

Galleries

As the borer pupae matures it will emerge as an adult flying beetle in June (see image 3) fly up into the canopy and feed on the leaves.  The adult will seek a mate and begin the lifecycle all over again by the end of summer. Prolific infestation and gallery spread will render the tree unable to move water and nutrient throughout its system and the ash tree will die within a short period of 2-5 years.  It is next to impossible to stop with the exception of pesticide treatment and parasitic insect enemies. Stressed trees will succumb much faster as healthier trees will resist and fight off the boring activity, but will too eventually succumb to the damaging infestations.

Image 3: EMERALD ASH BORER ADULT, EXIT HOLE IN BARK & SIZING COMPARISON

EAB SCALE

It is important as a homeowner in Connecticut that you take full stock of your trees on your property.  Knowing where the ash trees exist and what your plan is to treat or remove the tree(s) in the coming years is paramount.  As the tree declines it becomes more difficult and costly to remove and presents an even greater hazard to neighbors, town roads and personal property should it fail. If you think you have an ash tree and would like to get an assessment, please contact your arborist to get an action plan together.  Whether you plan to treat or remove, consider doing so soon to reduce costs and damages.  For a list of qualified arborists in your area please visit: www.ctpa.org also known as Connecticut Tree Protective Association.

One way of looking for EAB in your ash tree is look for woodpecker damage (See image 4) on the bark of the tree as well as the “D” shaped exit holes from the emerging adult. Ash trees will begin a slow decline as the upper canopy leaves begin to retreat and the tree will exhibit great crown reduction and dead limbs. Lower branch suckering and dieback will occur and within a short time the entire tree will be dead and require removal.  As the tree dies, the wood becomes very brittle and difficult to remove which is why it is necessary to identify and remove as soon as you find infestation.

Image 4: WOODPECKER DAMAGE TO BARK AND D-HOLES

Woodpecker Damage

For more information please visit: http://www.ct.gov/deep/eab​ and please feel free to contact your local arborist or Town Tree Warden to identify the tree, potential infestation and a treatment plan.

Bruce Lindsay – Town of Westport Tree Warden                             treewarden@westportct.gov

March 18, 2019

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