Ministry of Agriculture
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.
|Emerald Ash Borer Adult.
Photo Credit: David Cappaert, Michigan State University, Image 9000019, ForestryImages.org. http://www.forestryimages.org/. May 26, 2004.
|Emerald Ash Borer Larva.
Photo Credit: David Cappaert, Michigan State University, Image 1460071, ForestryImages.org. http://www.forestryimages.org/. May 26, 2004.
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.
Asia: China, Japan, Korea, Manchuria, Mongolia, Russia, Taiwan
Canada: Ontario - Essex County
USA: Michigan - Livingston, Macomb, Oakland, Monroe, Washtenaw, and Wayne counties
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.
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.
|Emerald Ash Borer Galleries.
Photo Credit: Ed Czerwinski, Ontario Ministry of Natural Resources, Image 1439009, ForestryImages.org. http://www.forestryimages.org/. May 26, 2004.
|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.
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.
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.