Emerald Ash Borer FAQ
Frequently Asked Questions about Emerald Ash Borer (EAB)
Does EAB kill all trees?
No. EAB only attacks true ash trees in the Fraxinus genus such as Green Ash, Black Ash and White Ash, Mountain Ash (genus Sorbus) is not a true ash and is not attacked by EAB.
Is my tree an Ash Tree?
If your tree has compound leaves (a leaf with many leaflets) and branches that grow opposite of each other, you may have an ash tree. These resources can help you learn how to identify if your tree is an ash tree:
- Ash Tree Identification (PDF), Michigan State Extension Service
- Distinguishing Ash Trees from Other Common Trees (PDF), Michigan State Extension Service
- Ash Tree Identification (PDF), Cornell University Cooperative Extension
- Minnesota Ash Trees, MnDNR website
How do I know if my tree is infested by EAB?
If your tree is an ash tree, it is vulnerable to EAB and will likely become infested. The signs of an early EAB infestation can be difficult to see. As the infestation grows (and greater harm is caused to the tree), the signs become more visible.
The most common signs of an EAB-infested ash tree are:
- High level of woodpecker feeding activity (bark flecking or "blonding")
- Thinning canopy and dieback
- Bark cracks and splitting
You are NOT likely to see an adult EAB (beetle). However, you may see an EAB larva if you look beneath the bark of an infested ash tree.
If you value your ash tree, the best course of action is to protect the tree from infestation instead of waiting to see if it becomes infested.
How does EAB kill ash trees?
EAB larva (immature beetle) eat the inner bark of an ash tree, essentially eating away the tree's circulatory system for transporting food and water. The inner bark does not grow back. Within 2 to 5 years of infestation the tree dies from lack of food and water. The amount of time it takes for an ash tree to die from an EAB infestation depends on the size of the tree and the size of the infestation.
If an ash tree has EAB, can it be saved?
An EAB-infested ash tree may be saved if the infestation is caught early (within the first couple of years of infestation) and the tree is otherwise healthy. However, once an infested ash tree has lost about 30% or more of its leaf canopy, it has become very compromised and is unlikely to survive even with treatment. Depending on the size and health of an ash tree, it may take anywhere between 2 to 5 years for a tree to die from an EAB infestation.
What can I do to protect my ash trees?
A pesticide treatment is the only reliable way to protect your ash tree from an EAB infestation. And a pesticide treatment may save an otherwise healthy tree with a mild EAB infestation.
For general health, you should also keep your ash tree properly watered and pruned (but avoid pruning during the EAB active season May 2 to September 30).
Who can perform the pesticide treatment?
For private trees, the City-allowed methods include trunk injection (recommended), soil injection, spraying, and soil drenching. However, soil drenching is not allowed for boulevard (right-of-way) trees and is not recommended for private trees because of environmental concerns.
While some pesticides are sold at retail locations, others may only be purchased and applied by a state-licensed commercial pesticide applicator. 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. You can also check the MDA Online Licensing System.
Also, any individual or company hired to do tree work (including pesticide work) in Burnsville, must be a City-licensed tree contractor. Find the list (PDF).
How much does the pesticide treatment cost?
The cost of treatment to protect an ash tree from EAB varies based upon pesticide, application method and tree size. Typical cost can range anywhere from $50 to $200, and some treatments last two years or more. Burnsville residents may take advantage of City contract pricing for EAB treatment for ash trees. Visit the main EAB page for more info.
How can I select a good tree care company?
Avoid door-to-door salesman and stick with reputable, established firms. The City of Burnsville maintains a List of Licensed Tree Contractors that have been evaluated for proper liability insurance levels and have an ISA-Certified Arborist on staff. If you're hiring a company to treat your ash tree, make sure that they have a valid commercial pesticide applicator license from the Minnesota Department of Agriculture.
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. However, if you have an ash in your yard and it is healthy, it is not necessary to remove it. Instead, consider planting a tree adjacent to your existing ash to avoid a drastic loss of shade if and when your ash tree must be removed. Burnsville maintains a list of recommended tree species (PDF).
What is the City doing about EAB?
In April 2013, Burnsville's City Council approved an Emerald Ash Borer Management Plan (PDF) that dedicates $3.5 million over 10 years to help protect good quality ash trees on public property, to remove others that become infested, and to plant new trees of different species to diversify our urban forest.
Ash trees in unmanicured woodland areas of parks will not be treated against EAB or removed unless necessary for safety reasons. Trees on private property will not be part of the City's treatment or removal plan.
What else can I do to help prevent the spread of EAB?
Adult (beetle) Emerald Ash Borers typically only fly short distances of about one-quarter mile, 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.
What are those Purple Boxes?
Residents may notice purple EAB traps hanging from ash trees in local parks. The Minnesota Department of Agriculture places these boxes to help with detection of new EAB infestations. The three-sided traps give off a scent that attracts nearby EAB beetles -- when the beetles land on the trap, they become stuck. The earlier an EAB infestation is identified, the better chance we have of eliminating that infestation.