Emerald Ash Borer

Green Man tree services are able to treat and control the Emerald Ash Borer ( EAB )  in Waukesha and Milwaukee.


Click on pic for a printable handout with info about EAB.

The Emerald Ash Borer has been confirmed in Waukesha County since 2012.  Green Man is one of only a few tree service companies that is licensed to treat existing tree infestations and also prevent the Emerald Ash Borer from infecting your trees.

Do you think you have an Emerald Ash Borer infection in one of your ash trees?  Contact us now! 

It may be possible to save the tree.  Green Man will do everything necessary to save and protect your trees from infection, if it is shown to be necessary, Green man tree removal services can properly dispose of the tree and remove the wood from your property.

EAB only attacks Ash trees, do you have an ash tree?
Ash TreeAn ash tree is most easily identified by:
1. It has an opposite branching pattern (two branches come off the main stem, one on each side and directly opposite each other)
2. It has compound leaves with 5-11 leaflets (depending on the species of ash). Leaflets are moderately toothed and may be stalked or sessile.
3. In winter: first look for the opposite branching pattern and stout twigs of ash. Small branches grow off larger branches opposite one another. Likewise, buds and leaf scars are opposite one another on twigs.
Next, Ash trees have many small dots (vascular bundles) on their leaf scars, forming a semi-circle or crescent pattern.
And, white and green ashes have thick, diamond-patterned bark, while black ash bark is thin, ashy-gray, and scaly.

How to Recognize an Emerald Ash Borer Attack

The symptoms an ash tree shows when it is infested with emerald ash borer are similar to symptoms caused by other ash pests or diseases in Wisconsin.
For example, crown dieback can occur due to EAB damage, but can also be the result of drought stress, soil compaction or verticillium wilt, just to name a few.
Therefore, it is important to look for a combination of at least two symptoms or signs when trying to figure out if emerald ash borer is in your ash tree.

Symptoms of Emerald Ash Borer

EAB larvae live under the bark and feed on the vascular tissues. Larvae create meandering galleries through the phloem, vascular cambium and etch the xylem, effectively girdling the tree. The tree responds by sprouting new (epicormic) branches below the disrupted tissues. Dieback of the canopy is a symptom of EAB larval infestation as many as one half of the branches may die back as infestation progresses. The bark will split over dead vascular tissues, and trees may die within only two years of the onset of symptoms.

Crown dieback: Dieback of the upper and outer crown begins after multiple years of EAB larval feeding. Trees start to show dead branches throughout the canopy, beginning at the top. Larval feeding disrupts nutrient and water flow to the upper canopy, resulting in leaf loss. Leaves at the top of the tree may be thin and discolored. An example of this is shown below.

Epicormic Sprouting: When trees are stressed or sick, they will try to grow new branches and leaves wherever they still can. Trees may have new growth at the base of the tree and on the trunk, often just below where the larvae are feeding. An example of this is shown in the picture above, where small branches are growing on the trunk, about 6 feet off the ground.

Bark splits: Vertical splits in the bark are caused due to callus tissue that develops around larval galleries. Larval galleries can often be seen beneath bark splits.

Woodpecker feeding: Woodpeckers eat emerald ash borer larvae that are under the bark. This usually happens higher in the tree where the emerald ash borer prefers to attack first. If there are large numbers of larvae under the bark the woodpecker damage can make it look like strips of bark have been pulled off of the tree.

Learn more

How to identify an Emerald Ash Borer

Emerald ash borer adults are very small, metallic green beetles. They are about the size of a cooked grain of rice: only 3/8 – 1/2 inch long and 1/16 inch wide.


When to Treat for Emerald Ash Borer

Treat ash if EAB is reported in your area. Do not wait for visible dieback in the canopy, as there is a significant delay between disruption to the vascular tissues and expression of symptoms in the canopy. Delaying Emerald Ash Borer treatment could result in canopy dieback or tree loss.


Injections can be made in the spring during the growing season, about 30 days prior to expected adult emergence. Uptake of formulation is fastest when trees are actively transpiring, after they have developed a full canopy. Emerald Ash Borer treatment in the spring will prevent the adult beetles from feeding and laying eggs in the tree.


Injections in the summer will kill the larval stage of EAB feeding under the bark. Make summer treatment applications in the morning when temperatures are moderate. If soil is dry, water trees prior to treatment.


Injections in the fall (before or after leaves color) can protect the tree now and the following season. The larvae are feeding now so they are doing a lot of damage to the vascular tissue. Proactive treatment is important since EAB larvae damage won’t exhibit symptoms until next year. The treatment will remain in the tree tissue and protect the tree through the next season.

Trees need to be closely monitored for symptoms of EAB as infestation builds in your area. In general, applications are not made more than once a year. Specific insecticide formulations for EAB may provide 2 years of activity.

Some Information on this page provided by Wisconsin’s Emerald Ash Borer Information Source.

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