| Emerald ash borer | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Coleoptera |
| Family: | Buprestidae |
| Tribe: | Agrilini |
| Genus: | Agrilus |
| Species: | A. planipennis |
| Binomial name | |
| Agrilus planipennis Fairmaire, 1888 |
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| Synonyms[1] | |
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The emerald ash borer, Agrilus planipennis, is a green beetle native to Asia.
In North America the borer is an invasive species, highly destructive to ash trees in its introduced range.[2] The potential damage of this insect rivals that of Chestnut blight and Dutch Elm Disease. Since its accidental introduction into the United States and Canada in the 1990s, and its subsequent detection in 2002,[3] it has spread to 14 states and adjacent parts of Canada. It has killed at least 50 to 100 million ash trees so far and threatens to kill most of the 7.5 billion ash trees throughout North America.[4] The emerald ash borer is now one of the most destructive non-native insects in the United States; it and other wood-boring pests cause an estimated $3.5 billion in annual damages in the U.S.[5]
The insect threatens the entire North American Fraxinus genus, unlike past invasive tree pests, which have only threatened a single species within a genus. The green ash and the black ash trees are preferred. White ash is also killed rapidly, but usually only after green and black ash trees are eliminated. Blue ash displays some resistance to the emerald ash borer by forming callous tissue around EAB galleries; however, they are usually killed eventually as well.[6]
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The adult beetle is dark metallic green, bullet-shaped and about 8.5 millimetres (0.33 in) long and 1.6 mm (1⁄16 in) wide. The body is narrow and elongated, and the head is flat with black eyes. The larvae are approximately 1 mm (1⁄25 in) diameter, 26 to 32 millimetres (1.0 to 1.3 in) long, and are a creamy white color. The eggs turn to a yellow brown color prior to hatching.[7] Adults lay eggs in crevasses in the bark. Larvae burrow into the bark after hatching and consume the cambium and phloem, effectively girdling the tree and causing death within two years. The average emerging season for the emerald ash borer is early spring to late summer. Females lay around 75 eggs, but up to 300 from early May to mid-July. The borer's life cycle is estimated to be one year in southern Michigan but may be up to two years in colder regions.
Life Cycle
The adult emerald ash borer emerges in May–July and the female lays numerous eggs in bark crevaces and between layers of bark. The eggs hatch in 7–10 days and larvae bore into the tree where they chew the inner bark and phloem creating winding galleries as they feed. This cuts off the flow of the water and nutrients in the tree, causing dieback and death.
The natural range of the emerald ash borer is eastern Russia, northern China, Japan, and Korea.
Its first confirmed North American detection was in June 2002 in Canton, Michigan. It is suspected, that it was introduced by overseas shipping containers being delivered to Yazaki North America. It has since been found in several other parts of the United States and Canada. Ohio, Minnesota, and Ontario have experienced emerald ash borer migration from Michigan. Additionally, Maryland and Virginia received shipments of contaminated trees from a Michigan nursery. The emerald ash borer was confirmed in Indiana in April 2004, in Central Kentucky in the Spring of 2009 and in Northeast Iowa in May 2010.
USDA APHIS PPQ used to attempt eradication of the insect, but its distribution is far too broad at this time and funds are lacking. Quarantine zones are still set up from which unprocessed raw hardwood material cannot be removed. The quarantine applies not only to the counties where the emerald ash borer has been detected but also high risk counties as well. The infected states have prohibited the movement of firewood from one state to another trying to eliminate the spread and fully enforce the quarantine zone. Large fines were imposed on a few companies that violated the ban, including one that was transplanting ash trees from southeast Michigan to Virginia and Maryland and is believed to be responsible for spreading the beetle to those states. The USDA has spent several hundreds of millions of dollars trying to minimize the ecological impact of EAB.
Michigan officials announced 2005-09-14 that ash borer infestation had crossed the Straits of Mackinac and was now in the Upper Peninsula for the first time. Wisconsin environmental officials consider it a grave threat and began preparations years ago for surveys in the state. Several counties in Indiana are under quarantine. However, states and cities are running out of money to combat the problem and many authorities feel that the borer will spread throughout North America. The EAB can move short distances by flying as well as surviving long distances in transit on ash tree nursery stock, Ash logs, branches, and firewood.
In June 2006, it was reported that emerald ash borers had been found at a home near Lily Lake, Illinois.[8] Illinois officials have regulated several counties because it was found to be widespread. In July, 2006, further infestations were discovered in northern Cook County, Illinois, including Wilmette, Evanston, and Winnetka.[9]
In June 2007, it was reported that emerald ash borers have been found in Cranberry Township, a suburb of Pittsburgh, Pennsylvania.[10] On June 27, 2008, The Pittsburgh Post Gazette reported that the state Department of Agriculture says the emerald ash borer has been found in Mercer County. The invasive beetle was discovered in Butler and Allegheny counties last summer. Officials are surveying this year to gauge whether the insect has spread. Mercer joins Allegheny, Beaver, Butler and Lawrence counties in a quarantine prohibiting the movement of ash nursery stocks, green lumber and firewood.
In October 2007, an emerald ash borer larva was discovered in a West Virginia Department of Agriculture "detection tree" located in Fayette County. This detection tree was located in a recreational site, with camping, mountain biking, and white water rafting. It is believed that the pest arrived in firewood that was illegally transported by tourists visiting the New River Gorge area, a popular site for white water rafting (USDA-APHIS-PPQ).[11]
As of December 2007, a federal quarantine has been imposed on the following areas in the U. S. for Emerald Ash Borer: the lower peninsula of Michigan; Mackinac County, Michigan; the entire states of Ohio, Illinois, and Indiana; Prince Georges County, Maryland; and Fayette County, West Virginia. (USDA-APHIS)
The state of Missouri has issued a quarantine for the entirety of Wayne County to prevent the beetle from leaving this area where it has been heavily detected.[12]
Emerald Ash Borer has also extended its distribution in Canada. As of August 2009, the following areas are regulated by the CFIA in Ontario: Essex, Lambton, Middlesex, Elgin, Huron, and Norfolk Counties, the Municipality of Chatham-Kent, the Cities of Hamilton and Toronto and the Regional Municipalities of Durham, York, Peel and Halton, the City of Sault Ste. Marie, and the City of Ottawa; in Quebec: The City of Gatineau and Municipalities of Carignan, Chambly, Richelieu, Saint-Basile-le-Grand and Saint-Mathias-sur-Richelieu.[13]
By June 2008, emerald ash borers were discovered in the city of Chicago,[14] and in the far south-west corner of Naperville.[15]
It was confirmed by Canadian Agriculture officials to be present in Monteregie, Quebec. This region lies directly north of New England, therefore drastically increasing the likelihood of being found in New England.[16]
On Tuesday, July 29, 2008, it was announced that the Missouri Department of Agriculture has detected the emerald ash borer in the state. On Monday, August 4, Wisconsin confirmed that the first appearance in the state was detected in the village of Newburg, Wisconsin, in Ozaukee County.[17]
On March 11, 2009 it was confirmed in Mifflin County, Pa. This county lies in the Eastern Central part of the state. As of August 12, 2010, the Pennsylvania Department of Agriculture reports that two-thirds of the state has been infested with the EAB, most in counties west of the Pocono Mountains.
The insect was furthermore detected in Victory, Wisconsin by agricultural officials on Tuesday April 7, 2009. This town is in the western part of the state, and borders Iowa and Minnesota. It is also along the Mississippi River, which may serve as a pathway for the insect.
On May 14, 2009, spread of the emerald ash borer was confirmed by the Minnesota Department of Agriculture in St. Paul, Minnesota.[18] This represents the most westerly location it has been found thus far in North America.
The New York State Department of Environmental Conservation announced on June 17, 2009 that the emerald ash borer was recently discovered for the first time within the borders of New York State, in the Cattaraugus County town of Randolph.[19]
The species was also detected in South Buffalo, New York in early 2011. As of August, 2011, the emerald ash borer was confirmed throughout Monroe County and in the City of Rochester.[20]
In early July 2011, City workers spotted the beetle in some trees in the southeast borough of Hochelaga-Maisonneuve in the City of Montreal. [21]
Authorities across the US are continuing to determine the exact extent of EAB by placing purple traps nationwide.
In 2011, the Emerald Ash Borer was found in traps on Manitoulin Island. The insect was found in July 2011, according to the Canadian Food Inspection Agency, and was identified in late autumn. The CFIA made a presentation to Northeast Manitoulin and the Islands town council on November 17, 2011.
Evidence of the emerald ash borer sometimes takes up to a year to recognize. Some signs that the emerald ash borer has infested a tree are D–shaped holes in the bark of the trunk or branches and shoots growing from the base of the tree.[7]
The beetle kills trees because the feeding larvae damage both the phloem (responsible for nutrient transport throughout the tree) and xylem (responsible for take-up of water and nutrients) tissues of the tree. The beetle effectively girdles the tree. As long as the beetle does not eat into the bark at the very base of the tree, these sprouts can still get nutrients to grow and can continue to grow even after the main trunk is cut down. Unfortunately, once these sprouts reach one inch in diameter, they then become attractive targets for the EAB.
The insect is unusually difficult to kill. More than 7.5 billion ash trees are currently at risk. Nearly 114 million board feet (33,000 m³) of ash saw timber with a value of US$25.1 billion is grown in the eastern United States each year. Over forty million ash trees have died or are dying in the United States at this time. The full time it takes for a tree to die due to the EAB is generally two or three years. The Emerald Ash Borer has killed nearly 30 million ash trees. Losses are estimated in the tens of millions of dollars.
The National Ash Seed Collection Initiative collects and stores ash seeds in cryogenic vaults at the National Center for Genetic Resources Preservation in Fort Collins, CO. If the population of American ash trees is destroyed, the stored seeds will be the genetic base to re-establish ash.
A pilot study is being undertaken in Michigan to determine if three different parasitic wasps can deter the emerald ash borer. These tiny stingless wasps can sense beetles underneath the bark and then lay their eggs in the larvae or egg, thus killing them. There have been doubts as to whether this biological control program will work, due to the fact that North American ash trees perish rapidly to the borer when they are planted in Asia, even where the parasitoids are present.[22] It is not known at this time whether their release will have any unintended ecological impacts.The wasps have been released according to a Michigan newspaper. The releases began in July 2007, a few weeks later than they had hoped.[23] (modification: USDA-APHIS-PPQ)
As part of the campaign against the emerald ash borer (EAB), American scientists in conjunction with the Chinese Academy of Forestry searched since 2003 for its natural enemies in the wild leading to the discovery of several parasitoid wasps, namely Tetrastichus planipennisi, a gregarious larval endoparasitoid,Oobius agrili, a solitary, parthenogenic egg parasitoid, and Spathius agrili, a gregarious larval ectoparasitoid. These have been been introduced and released into the United States of America as a possible biological control of the emerald ash borer. Initial results have shown promise with Tetrastichus planipennisi and it is now being released along with Beauveria bassiana, a fungal pathogen with known insecticidal properties.[24][25] [26]
Emerald Ash Borer-The Morton Arboretum