Emerald Ash Borer - Saving Wingra Park's Ash Trees

In May 2015, the Parks & Gardens Committee began a drive to raise $800 to pay for treating three ash trees in Wingra Park that provide critical shade for the playground area.  Neighbors donated an amazing $1056!  The lowest of three bids for treatment with Emamectin came from Tree Health Management at $630.  The trees will be treated by mid-July.  Signs will be posted on the trees to let people know.  Many thanks to all those who donated to the fund.  We expect that this year's injection will protect the trees until the spring of 2017.

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Information on the Emerald Ash Borer

The single best source of information on EAB in Wisconsin is at:  http://datcpservices.wisconsin.gov/eab/index.jsp

Other websites and information pertaining to Madison are given in the article below.  Mention of service providers should not be considered an endorsement by DMNA; the websites are provided for information and convenience only.

EAB Threatens Madison's Ash Trees

The emerald ash borer (EAB) was discovered in the Madison area in November 2013 and now threatens all our local ash trees.  Untreated, the EAB will destroy ash trees as the Dutch elm beetles destroyed the American elms.  Once a tree has been attacked by the beetle and begins dying, it must be removed and properly handled so as not to allow more insects to spread and destroy more trees.  Unfortunately, the ash has become the go-to urban tree; our streets are lined with ash trees that are now at risk. 

According to City Forestry staff, a third pocket of EAB was found along the 4600 block of Femrite Drive.  A total of 176 ash trees were removed in February 2014, making a total of 443 ash trees that have been removed preemptively since the first pocket of infestation was found.

Ash Trees Under Power Lines will be Removed Within 6 to 8 Years

In February 2014, Alder Sue Ellingson stated:  "Trees on the street belong to the City, not to homeowners.  The City will treat ash trees along the streets if the trees are at least 10" in diameter, in good health, and not under power lines.  The treatments will be implemented through 2016.  Street trees that do not meet those criteria will not be treated and will eventually be removed.  Many of the ash trees in D-M are under power lines.  At this time, homeowners do not have the option to treat street trees at their own expense.  They will be able to pay for treatments of ash trees in city parks through Adopt-a-Tree."

Check for Ash Trees on Your Street



What You Can Do

The City of Madison maintains a website with EAB information at:  http://www.cityofmadison.com/parks/services/forestry/pests/eab/

Do you have ash trees on your property?  Look at the leaves and branching pattern. See: Ash Identification: http://www.mda.state.mn.us/news/publications/ext/ashtreeid.pdf


If you have ash trees on your property, you will need to treat the tree with an effective pesticide or remove it; all varieties of ash trees are susceptible to the EAB regardless of the relative health of the tree.  If the decision is made to remove the tree, it is generally cheaper to remove a tree that is green rather than one that is dead.  Arrange for treatment of an ash tree that you want to save before it shows symptoms of EAB infestation.  Once symptoms appear, it is unlikely that the tree can be saved. 


How can I tell if my tree is already infected?  The best time to look for dead branches is in the winter while trees are dormant. Look for woodpecker holes and vertical bark splits. Look for 1/8 inch, D-shaped exit holes in trees. These are the result of borers leaving the tree once they have become adults. Peel back any loose bark on the trunk to look for S-shaped tunnels formed by larvae. This is a key indicator of EAB, as the only other common borer leaves linear tunnels in a zigzag pattern. Infected ash trees are slower to leaf out than healthy trees, and may have areas with stunted leaf growth. Generally, trees that are already infested with EAB cannot be saved by treatment.

What does an Emerald Ash Borer look like?

See: http://www.extension.umn.edu/garden/insects/find/emerald-ash-borer/

What are my management options? 

As with any new issue, property owners should be aware of the potential for unethical business practices and ineffective  products that may be available online or at stores.  Use information from reputable sources and check that any professional has the training and experience for the job.  


Effective treatments are available but depending on the specific product used, it must be applied annually or every two or three years to protect the tree.  Treatment consists of either injecting a systemic pesticide beneath the bark into the tissue that distributes sap or pouring a water-soluble pesticide over the tree roots near the trunk.  Under the proper conditions of soil moisture and in the spring and early summer, the pesticide is drawn up into the body of the tree and incorporated into the tree.  If an EAB egg hatches and the larvae burrows into the tree's cambium layer, the pesticide will kill the larva and protect the tree.  Due to the trauma of repeated drilling into the tree, injection treatment of ash trees is not recommended for small trees whose diameter is less than ten inches when measured four and a half feet up from the ground.


Property owners who wish to protect their ash trees can hire and follow the advice of a qualified professional.  Coordination with neighbors will reduce costs since it is more cost-effective to treat a larger group of trees at once. The pesticides available to professionals require training and a pesticide application license.  

These websites have more information on finding a qualified professional:  

Information is available for property owners who wish to treat their trees themselves at:  http://hort.uwex.edu/articles/homeowner-guide-emerald-ash-borer-insecticide-treatments.  Property owners should be aware that some of the chemicals are neonicotinomides, a class of pesticides that is being examined for its possible impact on the survival of honeybee hives.  Due to the concerns about protecting groundwater and the water quality of the lakes, the City strongly recommends treatment using direct injection, not the soil drench method.


The treatment window is between the start of leaf out and the beginning of hot weather in late June or early July.   More information is available from WI Horticulture/UW Extension at:  http://www.hort.uwex.edu/articles/protecting-your-tree-emerald-ash-borer


What can I do with the wood?

The simplest recommendation is to avoid moving the wood.  Removal of the bark will expose the EAB larvae to predators and stop them from maturing and invading other trees.  

Urban forestry entrepeneurs are looking to turn the wood into useful products.  Expect to see more companies develop markets as more trees become available.

Dane County has identified several areas with EAB, so felled ash trees cannot be moved outside the county.  Wood from ash trees infected with EAB can be used for lumber or fuel.  The state has regulations on the movement of firewood between counties at:  http://datcpservices.wisconsin.gov/eab/articleassets/Firewood_Movement_in_Wisconsin.pdf

Ash Trees in City Parks Won't be Treated

The City has decided that it cannot pay for treating ash trees in parks.  Residents may adopt an ash tree in a park and donate the cost of treatment.  See this website for more information about the Adopt-a-Tree park program.

EAB Myths

When any new threat appears, we are likely to hear both information and misinformation.  Here are some examples:

Myth:  Our winter was so cold that many of the overwintering insects were killed.

Reality:  No, the temperatures that Wisconsin experienced this winter were NOT cold enough to kill the larval stage of the EAB.  Temperatures need to stay in the -30 degree range for a time before the larvae would be killed.

Myth:  Only weakened or stressed ash trees are susceptible to EAB.  Healthy trees will resist the insects.

Reality:  All ash trees (green, white and ash and their variants) are susceptible to the EAB.  Even healthy trees are unable to resist the attack of EAB.  Note:  A "mountain ash" is not a true ash tree.

Myth:  We should do nothing and wait and see what happens.

Reality:  Doing nothing results in the rapid spread of EAB.  We know that the insect has been in Madison for at least three years, long enough to attack large numbers of trees.  It can take two to four years for the infected tree to show symptoms.  By the time symptoms are observed, hundreds of EAB larvae have devoured the cambium of the tree, depriving the tree of its tissue connection between leaves and roots.

Myth:  There are natural predators of EAB that should be used instead of pesticides.

Reality:  It is true that EAB has predators that keep its numbers in check in areas of China, where EAB originates.  However, research efforts are probably a decade away from having an effective biologic control.  We must rely on treatments that are available now.

What can we do to help the growth of the replacement trees?

As the ash trees currently growing under utility lines are removed, trees of shorter stature will be planted.  Residents can help these trees survive the challenging conditions found in urban areas.  DNR's Invasive Forest Insect Program Coordinator, Andrea Diss-Torrance, recommends the following:  " Watering, keeping mulch from piling up along the trunk, asking dog owners to keep them away from the thin-barked saplings (urine burns!), preventing lawn mower and grass trimmer damage all are easy and convenient for a resident to do.  Be a big brother or sister to a tree. "  More information is available in The Tree Owner's Manual.

Sources of Information

General information about EAB:  http://www.hort.uwex.edu/tags/emerald-ash-borer

Madison's official EAB information is available at:  http://www.cityofmadison.com/parks/services/forestry/pests/eab/

The City has a number of EAB-related publications available online at:  http://www.cityofmadison.com/parks/services/forestry/pests/EAB/toolkit.cfm

Want to learn more about the trees in Madison?  Go to

Madison's Emerald Ash Borer Plan - Sept 2013

[ Excerpts from WI State Journal 11/25/13]

Here are some of the plan's recommendations: 

• An injection chemical treatment program for terrace trees 10 inches diameter at breast height, except for trees in poor condition or under power transmission lines, that would begin when the borer is detected within 15 miles of Madison.

• Preemptively removing ash street trees in poor condition, taking out 200 trees in 2013 and 400 in 2014, with the extra trees next year to be part of two pilot canopy restoration projects in recently planted, newly developed neighborhoods. The city would also work with homeowners on pilot projects to remove small ash trees in fair to good condition.

• Removing ash street trees in poor condition or under power lines during infrastructure maintenance projects, and offering property owners the option to remove trees in fair or good condition during such public works projects.

• Replacing removed trees within a year or the next planting season.

• Giving property owners the option of chemically treating publicly owned trees in city parks at their own expense through an adopt-a-tree program that preserves legacy or high value trees and preserves tree canopy for environmental, economic or social reasons.