Emerald ash borer (EAB) is a highly invasive, non-native insect that attacks and kills all species of North American ash trees, including white, green and black ash. EAB is native to Asia and was first detected in the U.S. in summer 2002 feeding on ash trees in the Detroit area.  As of October 2009, EAB has not been confirmed in the northern Plains (Kansas, Nebraska, North Dakota and South Dakota).

Adult EABs are emerald green beetles that are approximately 1/2 inch long with slender, elongate bodies. EAB larvae can grow up to 1-1/2 inches long and are white or cream colored. They have a brown head and a 10-segmented body with a pair of brown, pincer-like appendages on the last segment.

EAB adults typically emerge during June and July, leaving D-shaped exit holes in the bark. After emerging, the adults feed on ash foliage and can live for approximately three weeks. Females lay eggs in the bark of branches and stems.

EAB larvae feed on the tissues just below the bark. As they feed, larvae create serpentine tunnels (galleries) that disrupt the tree's ability to transport water and nutrients, eventually killing the tree.

Symptoms of EAB include canopy dieback, beginning in the top one-third of the canopy, sprouting from the base of the tree and trunk, bark splitting, serpentine galleries below the bark, D-shaped exit holes and increased woodpecker activity.

Ash trees have an opposite leaf pattern, meaning that leaves and buds are located directly across from each other. Ash leaves are compound and typically consist of 5-11 leaflets. The edges of the leaflets may be smooth or toothed.

On mature ash trees, the bark has a distinct pattern of diamond-shaped ridges. Younger trees have smoother bark. When seeds are present, they appear in paddle-shaped clusters that stay on the tree until late fall or early winter.

As of April 2009, EAB has been detected in Michigan (both the upper and lower peninsulas), Illinois, Indiana, Kentucky, Maryland, Minnesota, Missouri, New York, Ohio, Pennsylvania, Virginia, West Virginia, and Wisconsin. In Canada, EAB has been detected in Ontario and Quebec.

Click here for a map of EAB locations.

To date, efforts to contain EAB have been unsuccessful. In the next several years we may have new methods for slowing EAB’s spread, but these will only slow its spread, not stop it.

In areas where EAB is present, insecticide treatments can be used to protect high-value trees, such as large shade trees, historic trees and trees valued by homeowners. Researchers are currently working to develop new treatments for EAB.

Insecticide treatments can be effective in protecting trees from EAB. One treatment available for homeowner use is a soil application of imidacloprid (such as Bayer Advanced Garden® Tree and Shrub Insect Control*). The application should be made in May and is most effective on small trees.

Tree care professionals are able to use additional products as trunk injections and trunk and foliage sprays. Contact a certified arborist to learn more.

Click here for more EAB control information.

*Mention of this product does not constitute an endorsement.

No treatment is needed until EAB has been detected within 15 miles of your location. If your tree has EAB-like symptoms, such as canopy dieback or D-shaped borer exit holes, have a certified arborist examine the tree.

To locate a certified arborist in your area visit the Nebraska Arborists Association (NAA) website at www.nearborists.org or the International Society of Arboriculture (ISA) website at www.isa-arbor.com.

If your tree is healthy, there is no reason to cut it down. If it is dying or diseased, it may be best to hire an NAA- or ISA-certified arborist to look at your tree and determine whether it has EAB or another insect or disease problem.

There are a number of native insects that attack ash trees, so just because your tree is displaying symptoms, doesn’t mean it has EAB. However, with highly destructive invasive insects, such as EAB, it is best to err on the side of caution by seeking professional guidance if you suspect your tree is infested.
If EAB becomes established in your area, management steps may need to be taken.

Ash has been popular in landscape, agroforestry and conservation plantings for decades. However, this popularity has resulted in a tremendous number of ash trees throughout Nebraska and the northern Plains. In Nebraska alone there are an estimated 37 million ash trees!

Species diversity is an important measure of a community forest’s overall health, so it is important to plant a variety of tree species. Because EAB is such a significant threat to our state's tree resources, the Nebraska Forest Service no longer recommends significant planting of ash trees native to North America, including green ash (Fraxinus pennsylvanica), black ash (Fraxinus nigra), blue ash (Fraxinus quadrangulata) and white ash (Fraxinus americana). This also includes popular cultivars, such as 'Patmore' green ash and 'Autumn Purple' white ash. For more detailed information, please see the NFS Position on Ash.

However, there are a number of trees that grow well in Nebraska, but are frequently under planted. For recommendations about what trees you can plant in your landscape and a list of where you can purchase these trees, visit ReTree Nebraska at www.retreenebraska.unl.edu.

There are a number of trees that will grow well in Nebraska, but aren't widely planted. To promote these species, ReTree Nebraska has developed a list of Good Trees for the Good Life. To learn more about these trees or find out where you can purchase them, visit www.retreenebraska.unl.edu.

Species diversity is a common measure of a community forest's overall health. In a sense, increasing species diversity prevents us from "putting all our eggs in one basket" and prohibits any single insect or disease from destroying a community's entire forest resource. Pine wilt, Dutch elm disease the approach of EAB all reinforce the importance of species diversity. In fact, forestry experts recommend that no single species make up more than 10 % of the entire community forest resource.

Contact your local nursery for suggestions about appropriate species for your landscape.

There are several species of native borers that attack ash trees. The banded ash clearwing, carpenterworm and ash/lilac borer attack healthy ash trees. The redheaded ash borer, banded ash borer and eastern ash bark beetle all attack stressed or dying ash trees.

For more information about these insects, see Michigan State University Extension Bulletin E-2939, Native Borers and Emerald Ash Borer Look-alikes.

There are limited options available for treating and using infested ash wood to ensure that EAB will not be spread through contaminated lumber or wood products.

For more information, contact the Nebraska Department of Agriculture at (402) 471-2394.

The Nebraska Forest Service (NFS) is involved with the Great Plains Tree and Forest Invasives Initiative (GPI), a collaborative initiative of state forestry agencies in Kansas, Nebraska, North Dakota and South Dakota and the U.S. Forest Service. The goal of GPI is to prepare for the arrival of invasive insects, such as EAB, in the northern Plains. Click here to learn more about GPI.

With an initial focus on EAB, states are inventorying regional tree and forest resources to determine which areas may be most impacted by EAB and other invasive species, developing public education programs, establishing citizen-based monitoring and detecting networks and exploring opportunities for utilizing wood generated by EAB.

To provide further assistance, the group is creating a template for communities across the northern Plains to use when developing local readiness and response plans.

NFS is also part of Nebraska's Emerald Ash Borer Working Group, a group of resource agencies dedicated to preparing for EAB's arrival in Nebraska. The group is deeply involved with developing a state-level readiness and response plan that will help state and federal agencies work closely with communities across the state to minimize the impacts of EAB infestations.

To find out more about EAB, email NFS at trees@unl.edu or call the Nebraska Department of Agriculture at (402) 471-2394. Information is also available online at www.emeraldashborer.info.

If you suspect your ash tree has EAB, contact the Nebraska Department of Agriculture at (402) 471-2394 or the National EAB Hotline at (866) 322-4512.

For more information about EAB, GPI or Nebraska's EAB Readiness and Response Plan, contact Steve Rasmussen at srasmussen2@unl.edu or (402) 375-0101.

Contact Information

To find out more about EAB, email NFS at trees@unl.edu or call the Nebraska Department of Agriculture at (402) 471-2394. Information is also available online at www.emeraldashborer.info.

If you suspect your ash tree has EAB, contact the Nebraska Department of Agriculture at (402) 471-2394 or the National EAB Hotline at (866) 322-4512.

For more information about EAB, GPI or Nebraska's EAB Readiness and Response Plan, contact Steve Rasmussen, GPI coordinator, at srasmussen2@unl.edu or 402-375-0101.