Emerald Ash Borer

EAB is a small, brilliant green beetle about the same size as the native Bronze Birch Borer, which kills white birch. These adults lay eggs on the bark of ash trees. Upon hatching, the tiny larvae bore under the bark and begin feeding in the cambial layer (the transport system) of the tree. These larvae feed in winding serpentine patterns under the bark, essentially girdling the trees as they go. Upon maturing, the adult exits the bark forming a distinctive "D" shaped exit hole. Signs to look for include bark cracking, crown dieback, heavy woodpecker activity and sprouts on the trunk of the tree. It usually takes 2-5 years for the tree to fully show damage from EAB. Unfortunately, many of these signs are also indicative of other disease and insects that already infect our ash. If you suspect that your trees may have this insect, please contact the Forestry Division, a County horticulture agent, or a Department of Natural Resources (DNR) Forest Health Specialist. For more information on EAB please read the Wisconsin Emerald Ash Borer Resource Guide.

City of Manitowoc EAB Management Plan

In 2009, the City of Manitowoc worked with surrounding communities, as well as local and state agencies to form and maintain an EAB management plan. The most recent version of the plan can be found by clicking on this link:  EAB Management Plan.  

EAB Within the City of Manitowoc
On July 26, 2017, the City of Manitowoc received confirmation from the Wisconsin Department of Natural Resources that Emerald Ash Borer (EAB) was detected in the City for the first time.  EAB was confirmed in the 900 block of S. 20th St., and infested trees were seen on public and private property in the immediate vicinity.  Most of the City-owned trees will typically be removed by the Forestry crew between late fall and early spring when EAB is inactive.

Finding EAB in the City came as no surprise.  Manitowoc County was under quarantine for EAB since 2014, when infestations were found in neighboring Calumet and Sheboygan Counties.  The first detection of EAB in Manitowoc County was on private property in the Town of Schleswig in 2016. 

EAB has been found to be nearly 100% fatal to untreated Ash trees.  Property owners with Ash trees should keep a close watch for signs of possible EAB infestation, such as thinning of the canopy, D-shaped exit holes in the bark, new branches sprouting low on the trunk, cracked bark, and woodpeckers removing the bark to get to the insect larvae beneath it.  Mountain Ash, however, is not susceptible to the insect. 

Ash owners should consider protective insecticide treatment after considering several factors, including the current structural and health condition of the trees, age, size, and the number of trees.  Treatment costs vary depending on the size of the tree and whether treatments are done by the property owner or a professional.  Residents should contact an ISA Certified Arborist for expert advice about treating or removing Ash trees.  Residents who remove their Ash trees should consider tree replacement with different species that are not susceptible to EAB.

Frequently Asked Questions (FAQs)

If I think my terrace tree is infected, what do I do?
E-mail the Forestry Division at forestry@manitowoc.org, file a Report-A-Concern issue, or call the Forestry office at (920) 686-3580 and report the tree.  The tree will be inspected by the City Forester.  If an infestation is confirmed, the tree will typically be scheduled for removal from late fall to early spring when EAB are inactive.

I have a healthy looking terrace Ash tree I want to have removed.  What do I do?
We have your tree inventoried.  If it is a healthy tree, no action will be taken at this time.

What kind of treatment options are there for Ash trees and what is the cost?
The City does not treat terrace trees.  If you have a private tree you are concerned about you can contact a local ISA Certified Arborist.  The city does not make recommendations for ISA Certified Arborists.

I want to keep my infected terrace tree.  Can I pay to have the tree treated?
Yes.  The City Forester will inspect and confirm EAB.  Treatment of trees will be handled on a case by case basis by the City Forester.

Will the City remove the stump and replace an Ash tree removed?
The City will remove stumps in the terrace area and fill/seed.  Trees may be replaced when funds become available. 

Will the City Forester give me advice on a tree on my private property?
No.  You will need to contact an ISA Certified Arborist for advice.

Who are the ISA Certified Arborists in the area?
The City does not make recommendations.  A directory of ISA certified arborists can be found by visiting www.treesaregood.org.

Am I able to keep the wood from my terrace tree if it is cut down?
EAB affected trees will be sold at the standard fee charged for any other wood.  Wood should be used as firewood for that property and should not be moved, sold or transported outside the quarantine area.  Wood must be burned before April 1st of the next year to help reduce the spread of EAB.

What can I do as a homeowner with the wood from my private tree?
Manitowoc is under EAB quarantine.  It is a system of rules intended to help prevent the spread of EAB.  The rules restrict the movement of firewood and ash products out of the quarantined areas.  Quarantines are administered by the USDA Animal and Plant Health Inspection Service and the Wisconsin Department of Agriculture, Trade and Consumer Protection.  Violations of the quarantine rules can result in State and federal fines up to $1,000.00.  For more information go to www.emeraldashborer.wi.gov and click on firewood regulations.

Related Links

These websites offer more detailed information about EAB: