Frequently Asked Questions

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Frequently Asked Questions

Information Prepared By:
Michigan Department of Agriculture
Michigan Department of Natural Resources
Michigan State University
U.S. Department of Agriculture APHIS and Forest Service

Where did this Emerald Ash Borer come from?

At this point no one knows specifically how it arrived in Michigan. It is an exotic pest species.  The natural range of Agrilus planipennis, or the Emerald Ash Borer, is eastern Russia, Northern China, Japan, and Korea.

What is the Emerald Ash Borer?

The Emerald Ash Borer, Agrilus planipennis, is an exotic insect pest that has been discovered in ash trees in southeastern Michigan.

What types of trees does the Emerald Ash Borer affect?

To the best of our knowledge it has only been found on ash trees, hence its name. Trees in wood lots as well as landscaped areas are affected. For the most part, affected trees appear to be at least 2 inches in diameter and larger.

Where has it been found?

To date, infested trees have only been found in Livingston, Macomb, Monroe, Oakland, Washtenaw and Wayne Counties. Inspections are continuing in other areas of the state. It has also been detected in Windsor, Ontario of Canada and a small portion of Lucas County, Ohio.

What symptoms does a tree infested with the borer exhibit?

Infested trees exhibit top-down dieback typical of other phloem borers such as two-lined chestnut borer. It has been observed that one-third to one-half of the branches may die in one year. Most of the canopy will be dead in two years. Affected trees may have vertical splits in the bark 2-4 inches long. Often dense sprouting of shoots can been found arising from the trunk or roots.  Although difficult to see, the adult beetles make a "D"-shaped exit hole in the bark, roughly 1/16 inch in diameter.

What do Emerald Ash Borers look like?

The adult beetle is dark metallic green in color, 1/2 inch in length and 1/16 inch wide.

What is the life cycle of this borer?

The beetle appears to have a one-year life cycle. Adults begin emerging in late May with peak emergence in mid-June. Egg laying occurs soon after adult emergence. After hatching, the borer goes through several larval stages, overwinters as a larva, then pupates in late spring.

How is this pest spread?

The ash borer can be spread through movement of infested trees or in logs and firewood. The borer is a good flier, although it is doubtful that it could fly long distances. Most likely, local spread would occur by movement of infested material and adult flight, while long distance spread would occur due to movement of infested material or other human activities.

How long has the Emerald Ash Borer been in Michigan?

No one knows for sure. Experts feel that it may have been in the Detroit area as long as five years, based on the age of trees affected and when tree dieback was first observed.

Does it only attack dying or stressed trees?

While many of the trees affected by this ash borer appear to have been stressed by drought, disease or poor soil, in many instances healthy trees were also infested and killed by the borer.

What are other insects may attack ash trees?

It is not uncommon for diseases or dying trees to be attacked by secondary borers once the tree is weakened. Some of the secondary pests attacking ash include larvae of various native cerambycid beetles, clearwing moths or even certain Diptera species.

What is being done on a statewide basis about this new pest?

An Emerald Ash Borer Task Force has been formed to address and respond to managing this pest and related issues. Task Force members include the Michigan Department of Agriculture, the Michigan Department of Natural Resources, Michigan State University, Michigan Technological University, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service and Forest Service, plus county and municipal officials.

Who do I call to get more information on the Emerald Ash Borer or to report an infested tree?

Contact local offices of the Michigan Department of Agriculture, Michigan State University Extension or the Michigan Department of Natural Resources. You may also contact the Emerald Ash Borer Hotline toll-free at (866) 325-0023. Information will also be available on the State of Michigan web site at www.michigan.gov and using the key word – ash borer.

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The City of Ferndale, Michigan
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Ferndale, Michigan  48220
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