Emerald ash borer

Distribution

It is common for all the trees in a single neighborhood to die at the same time. In a typical small town /city situation, the 4 year period, from year 8 through year 11 after infestation, will see 60 - 70% of their trees die in that region. They are calling this the curve of death because on a graph that charts time and tree death after beetle introduction, the plotted line angles almost straight up during those 4 years, ending in all the local ash trees being dead. As insects migrate, new epicenters of Ash tree mortality pop up more and more frequently. These then begin to coalesce. This pattern will continue until eventually, all the ash are dead.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, an automotive parts distributor. 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. 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.

In June 2007, it was reported that emerald ash borers have been found in Cranberry Township, a suburb of Pittsburgh, Pennsylvania.
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 .

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.

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.

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.

By June 2008, emerald ash borers were discovered in the city of Chicago, and in the far south-west corner of Naperville.

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.

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.

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. This represents the most westerly location it has been found thus far in North America. Minnesota has more ash trees than any other state in the United States.

In the summer of 2011, the Minnesota Department of Agriculture introduced tiny, stingless wasps in the Minneapolis-St. Paul metro area as a biological control agent for the emerald ash borer.

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.

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.

In early July 2011, City workers spotted the beetle in some trees in the southeast borough of Hochelaga-Maisonneuve in the City of Montreal.


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.

Status

In North America the borer is an invasive species, highly destructive to ash trees in its introduced range. 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, it has spread to 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. 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.

Behavior

EAB may take one or two years to complete its life-cycle depending on 1) the timing of egg deposition, 2) the health and stress level of the tree, and 3) local temperatures. The one-year EAB life-cycle is described below.


Adults
The adult beetle is dark metallic green, bullet-shaped and about 8.5 millimetres long and 1.6 mm wide. The body is narrow and elongated, and the head is flat with black eyes. Adults begin to emerge from the trunks of ash trees after the accumulation of 400-500 growing degree days base 50°F . Peak adult emergence occurs at ~1000 GDD. After emergence, adults fly into the ash canopy where they feed on leaves throughout their lives. EAB adults start mating one week after emergence, and females begin laying eggs 2-3 weeks later. In the field, EAB adults are readily observed mating and egg-laying on the trunks of ash trees on warm, sunny afternoons and evenings. The adults of both sexes are strong fliers.


Eggs
A female EAB may lay >100 eggs in her lifetime, depositing them individually or in groups on the bark along the trunk and portions of the major branches. Eggs are laid in areas where the bark is rough, and between bark layers or in bark crevices. Eggs are approximately 1.0 mm long x 0.6 mm wide and creamy white when laid; fertile eggs gradually turn amber after a few days. The eggs hatch after about two weeks.


Larvae
Newly hatched larvae bore through the bark to the phloem and outer layer of new sapwood where they feed until the weather gets too cold in the fall. There are four stages of larval development (instars. As they feed, the larvae create long serpentine galleries filled with frass, which enlarge in width as they grow. Larvae are creamy white, and dorso-ventrally flattened. When fully mature, fourth-instar larvae are 26 to 32 mm long. Their head is mostly retracted into the prothorax with only the dark brown mouthparts visible. The prothorax is enlarged, with the mesothorax and metathorax more narrow. Larvae have 10 bell-shaped abdominal segments and a pair of small brown structures called urogomphi, which are characteristic of all larvae in the genus Agrilus.


Overwintering larvae, pre-pupae, pupae, and adults
In the fall, mature fourth-instar EAB larvae excavate pupal chambers in the sapwood or outer bark where they fold into overwintering “J-shaped larvaeâ€. In the spring, the J-shaped larvae shorten into prepupae then shed their cuticle to become naked pupae. Pupae
are initially creamy white, but the eyes turn red and the body begins to darken as they develop. To emerge from ash trees, adults chew D-shaped exit holes through the bark and are capable of immediate flight upon emergence. EAB larvae that are immature as cold weather arrives in the fall will simply overwinter in their larval gallery. Larger larvae complete development the following spring, whereas smaller larvae may require another summer of feeding to complete development.

Habitat

Cities such as Minneapolis, Minnesota have slightly more than 20% of their urban forest as ash. This is typical; as many cities have high ash populations because of their ability to tolerate urban stress and survive poor planting practices that plague urban cities today. The Minneapolis / St. Paul metro area has between 2 - 2.5 million ash.

All towns and cities with significant ash populations will be eventually invaded by the Emerald Ash Borer and go through the EAB curve of death. How a town or a city prepares for this arrival is important. Having no plan will mean trees will die quickly. Dead Ash trees will be everywhere, faster then expected. Dealing with this scenario carries a very high cost. However, having a planned management strategy will cost far less, spreading these costs out significantly longer. In addition, important ash trees will be alive for many years - for less expense than removal and replacement.