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Emerald Ash Borer
The emerald ash borer (Agrilus planipennis) is a destructive pest of
ash trees that has recently been introduced to North America from Eastern Asia.
It was first detected in Canada and the United States in 2002, but the pest has
likely been present for 4 to 5 years in both countries. Surveys conducted by the
Canadian Food Inspection Agency (CFIA) in 2003 indicate that the pest is confined to
Essex County in Ontario (Windsor area). The beetle is also established in
Michigan State in the U.S. It has not been detected in British Columbia.
The emerald ash borer is a major economic and environmental threat to both
urban and forested areas of Canada and the United States, and is of concern to
British Columbia. It has already
demonstrated its destructive potential by infesting an estimated 100,000 to
200,000 ash trees in Essex County, Ontario, and by killing over 6 million ash trees in
Michigan.
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Emerald Ash Borer Adult.
Photo Credit: David Cappaert, Michigan State University, Image 9000019, ForestryImages.org. http://www.forestryimages.org/.
May 26, 2004.
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Emerald Ash Borer Larva.
Photo Credit: David Cappaert, Michigan State University, Image 1460071, ForestryImages.org. http://www.forestryimages.org/.
May 26, 2004.
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Appearance
Adults: metallic blue-green beetles, 8.5-14.0 mm (about ½ inch)
long and 3.1-3.4 mm (1/8 inch) wide, body elongated, head flat.
Larvae: 26 - 32 mm long at maturity, creamy white in colour, brown
head, flat, broad shaped body; 10-segmented abdomen.
Pupa: 10 -14 mm long, creamy white in colour.
Distribution
Asia: China, Japan, Korea, Manchuria, Mongolia, Russia, Taiwan
Canada: Ontario - Essex County
USA: Michigan - Livingston, Macomb, Oakland, Monroe, Washtenaw, and
Wayne counties
Hosts
The emerald ash borer attacks and kills all species of ash (Fraxinus
spp.). Note, mountain ash (Sorbus spp.) is not a host. There are reports
from Asia of walnut and elm also being affected, but this has not been observed
to date in North America.
Damage:
Infested trees show general symptoms of dieback and decline. Tree death has
been observed to occur within 1 to 3 years. Larvae feeding under the bark cause
serpentine galleries or tunnels. The galleries range in length from 9 to 30 cm,
and are filled with sawdust and frass. Most galleries are
located in the basal portion of the tree trunk, and are not visible unless the
bark is removed. When adults emerge, they leave D-shaped exit holes in the
bark, about 3-4 mm wide. Callus tissue produced by the tree in response to
larval feeding may cause short vertical splits to occur in the
bark above a gallery.
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Emerald Ash Borer Galleries.
Photo Credit: Ed Czerwinski, Ontario Ministry of Natural Resources, Image 1439009, ForestryImages.org. http://www.forestryimages.org/.
May 26, 2004.
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Emerald Ash Borer D-shaped Exit Hole.
Photo Credit: David R. McKay, USDA APHIS PPQ, Image 1439002, ForestryImages.org. http://www.forestryimages.org/.
May 26, 2004.
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Life Cycle
Adults lay eggs on the bark of ash trees, often inside bark cracks and crevices,
from early June to late July. Eggs hatch within about 2 weeks into larvae,
which chew into the inner bark (cambium) of the tree where their feeding
creates tunnels or galleries. The larvae overwinter under the bark, pupate in the spring, and emerge as
adults in May and June.
Adults are active during the summer months. They eat small amounts of
foliage, but it is the larval stage that causes tree damage and death.
How it Spreads
Emerald Ash borer beetles can fly up to several kilometers to seek new host material.
Long distance dispersal is generally the result of people moving infested
materials. The emerald ash borer can be spread to new areas on firewood, nursery stock,
trees, logs, and any lumber or wood with bark attached, including bark chips.
It is thought that the insect was brought into Canada on wooden packaging
material - a common entry pathway for wood-boring insects.
Quarantine Regulations:
The CFIA has established a quarantine zone including all of Essex County in
Ontario (Windsor, Amherstburg, Essex, LaSalle, Tecumseh, Lakeshore, Kingsville
and Leamington). The quarantine restricts the movement of regulated material
out of the area, including ash nursery stock, ash trees, logs, lumber, wood,
wood chips or bark chips, firewood of all tree species, and vehicles that were
used to carry these articles. Moving these articles from the quarantine area to
other areas of Canada is only allowed when a Movement Certificate has been
issued by a CFIA plant protection inspector.
In addition, an Ash Free Zone has been established around the infested area. All ash trees in an 8 to
10 km buffer zone, which falls in the municipality of Chatham-Kent, have been, or will be removed to prevent natural spread of the
beetle. Propagation of ash trees is prohibited in the control area.
Compensation will be available to property owners for
the replacement of trees that have been ordered destroyed.
Further Information:
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