For some time now, the Emerald Ash Borer (EAB) has been the predominant topic of discussion when it comes to forest pests, particularly in the eastern United States.  It’s naturally found in northern China, Japan, Korea and eastern Russia, and found its way over to our shores sometime in the summer of 2002.

Our Arborjet associates describe the Emerald Ash Borer as “an invasive pest 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.”

Emarlad Ash Borer

Emerald Ash Borer (EAB)

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Know what to look for when assessing EAB infestation on your property.  Typically, “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, and 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.”

Emerald Ash borer damage

“D”-shaped holes created by the EAB

Damage from Emerald Ash Borer

“Galleries” (Channels) made by the EAB

Die-back from Emerald Ash Borer

Ash crown die-back due to EAB infestation

When to Treat

We agree with our Arborjet colleagues that you should consider treatment as soon as EAB is reported to be 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.”  Again, trees need to be closely monitored for symptoms of EAB as infestation increases in your area.

What to Expect After Treatment

Depending on the extent of the infestation and the inherent vigor of the tree, treatments may effectively terminate the existing EAB insect, stop the infestation from spreading, and give the tree a chance to recover.

FORECON is well-equipped to assess, prescribe and administer the necessary treatments to help preserve your ash trees from the ravages of the EAB.  Please fill out the form on this page, or give us a call to discuss your situation and develop the proper plans to slow or eliminate the EAB from doing damage to your valuable ash trees.

Main Office Phone: 716.664.5602

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