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Emerald Ash Borer FAQ
Frequently Asked Questions About EAB:
Information adapted from Minnesota Department of Agriculture and University of Minnesota Extension.

What are the symptoms of EAB?
Evidence of emerald ash borers
Trees typically are killed in two to four years. When trees are first attacked by EABs, the symptoms are inconspicuous and hard to notice. By the end of the second year, thinning foliage and dieback in the crown begins to be apparent. By the third year, there is severe dieback and little foliage. Ash can tolerate small numbers of EAB larvae but trees are girdled and killed when populations become more numerous.

When the adults emerge, they create small, 1/8 inch D-shaped exit holes that are characteristic of this insect, although they can be hard to see. If you were to remove the bark on the trunk of a tree showing these symptoms, you should also find the larval galleries. Epicormic sprouts may form on the lower trunk and major branches as the tree responds to emerald ash borer activity. Woodpecker attacks on ash could also indicate the presence of emerald ash borers. Vertical splits in the bark due to callous tissue forming over old galleries may also be seen.

D-shaped exit holes from adults emerging Damaged trees

All species of Minnesota’s 900 million ash trees are vulnerable to attack, including: green (F. pennsylvanica), black (F. nigra), and white ash (F. americana). Mountain ash (Sorbus. spp.) is not a true ash and is not attacked. Emerald ash borer attacks ash of different sizes from as small as one inch diameter to large mature trees. They commonly attack stressed and unhealthy trees first, similar to the native bronze birch borer and twolined chestnut borer. However, unlike these insects, EABs will also successfully attack vigorously growing trees. Once an ash is infested by EABs, it will be killed.

What can I do to protect my valuable ash trees?
First, keep your trees healthy by properly watering and pruning them. Try to avoid pruning during the growing season. Second, watch your ash trees for signs of infestation. If you notice these signs, contact the City forester or a tree care company with a certified arborist on staff. For valuable ash trees, there is an annual pesticide treatment that can be applied to the tree to increase the chances of saving the tree from EAB damage. These treatments, however, must begin before the infestation has reached 35 percent to 40 percent of the tree – otherwise the treatment may be ineffective.

For more detailed information on insecticide recommendations, visit or call the Burnsville Forestry Department at 952-895-4508

How does the insecticide treatment work?
The basic approach to EAB control is an injection treatment. Treatments do require specialized equipment and training and should be performed by a licensed tree care specialist. Soil drenching is not permitted in Burnsville by ordinance 3-29-5.

Who can perform the pesticide treatment?
Only someone with a Minnesota commercial pesticide applicator license may apply pesticide for hire. The Minnesota Department of Agriculture (MDA) recommends that property owners ask to see an applicator's identification card and verify that the license is current and includes turf and ornamental licensure before allowing any application work on their property. Property owners may also contact the MDA at 651-201-6615 to verify proper licensing.

How much does the pesticide treatment cost?
While the exact amount varies, the cost ranges between $50 and $200 per year per tree.

How can I select a good tree care company?
Avoid door-to-door salesman and stick with reputable, established firms. The City of Burnsville has a  List of Licensed Tree Contractors that are licensed to do tree removal, trimming and injections. They will have an ISA Certified Arborist on staff and have a valid commercial pesticide applicator license from MDA.

Should I be planting or removing ash trees?

Because of the overabundance of ash in urban landscapes and other sites, it is strongly recommended not to plant additional ash. Consider planting other tree species, especially native trees that are well adapted to Minnesota conditions and are less likely to be stressed. However, if you have an ash in your yard and it is healthy, it is not necessary to remove it at this point. Instead, consider planting a tree adjacent to your existing ash to avoid a drastic loss of shade if and when your ash tree dies. Burnsville maintains a list of recommended tree species.

What is the City doing to prepare for EAB?
In April 2013, Burnsville's City Council approved an updated Emerald Ash Borer Plan that dedicates $3.5 million over 10 years to help protect some existing ash trees on public property, remove others that become infested and plant new trees.

The City has approximately 3,000 ash trees in its boulevards, 930 in parks and 14,300 in public woodlands. There are also more than 22,000 ash trees found on private property. The dedicated funds will allow the City to treat 2,865 “legacy” ash trees in parks and boulevards prior to the arrival of the ash borer. It will also cover the removal of 1,100 poor condition ash trees on public property – 50 percent of which will be replaced with new trees.

Remaining trees would be left untreated, and only removed if necessary for safety reasons. Trees on private property will not be part of the City’s treatment or removal plan. Residents who wish to treat private trees can do so using the City’s contracted price beginning in 2014.

What else can I do to help prevent the spread of EAB?
Adult emerald ash borers can only fly about one quarter mile per year, so the natural spread of the destructive insect is slow. However, humans have helped EAB spread by moving infected firewood and other wood products from an infested site. Do not move firewood—even if you intend to burn it promptly. The insects can escape from the wood quickly and infect new sites. The best prevention is to keep EAB contained.

*Images Courtesy of

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