Emerald Ash Borer
The Emerald Ash Borer (EAB) is an invasive pest introduced from Asia that attacks ash trees (Fraxinus spp.) This metallic wood boring beetle was found in Detroit, Michigan and Ontario, Canada in 2002, and has continued to spread into neighboring states and eventually across the U.S. and Canada. The adult is a small, metallic green beetle only 10-15 mm in length and about 3 mm in width. The larvae live under the bark of the tree and feed in the vascular cambium. The adults typically emerge around June, leaving D-shaped exit holes in the bark. This ash tree insect briefly feeds in the canopy before reproducing and laying eggs in the twigs and branches.
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.
Photo A taken by Dave Cappaert
Photo B taken by Pennsylvania Department of Conservation and Natural Resources - Forestry Archive, Bugwood.org
Photo C taken by Joseph O'Brien, USDA Forest Service, Bugwood.org
Photo D taken by Arborjet, Inc
Emerald Ash Borer's effects in Elgin, IL.
Emerald Ash Borer is devastating thousands of communities like this. It can cost $800-$1,200 to remove dead ash trees. Treatments with TREE-äge® are protecting ash trees at a fraction of the cost.
*TREE-age® insecticide is a Restricted Use Pesticide and must only be sold to and applied by a state certified applicator. TREE-age® is not registered for use in all states. Please check with your state or local extension service prior to buying or using this product. TREE-age® is registered trademark of Arborjet, Inc.
When to Treat
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.
What to Expect After Treatment
Trees will recover from infestation and will be protected from Emerald Ash Borer.
See research results.
Municipal Strategies for Managing Emerald Ash Borer webinar recording
Baltimore Emerald Ash Borer Treatment Demonstration