The invasive organisms quickly spread and caused massive die-offs of both chestnuts and elms, forever altering the composition of U.S. forest ecosystems and leaving behind the names of streets that today are but written memories of these once mighty shade- and wildlife-habitat givers.

Decades later, in 2002, another Asian import — this time an insect — was discovered in Detroit, feeding on and killing ash trees, whose hardwood is used to make the bats that have helped make baseball the nation's favorite pastime for over a hundred years.

Six years later, emerald ash borer (EAB) has turned from an emerging pest into one of the most significant environmental threats facing North America. From its initial epicenter in greater Detroit and western Ontario, Canada, EAB has so far infested a total of seven Midwestern and Eastern states from Illinois to Maryland, killed millions of trees, overwhelmed municipal budgets, and practically halted the region's once profitable production of ash trees for landscaping (in Ohio this segment of the nursery industry was worth over $20 million when EAB was found in the Toledo area in 2003).

Not to mention the still uncertain ecological impacts this exotic beetle is expected to have on the forests.

Just like chestnut blight and Dutch elm disease before it, EAB is capable of wiping out an entire species of trees from North America, said Dan Herms, an entomologist with the Ohio Agricultural Research and Development Center (OARDC) and Ohio State University Extension.

That's why Herms — Ohio's representative on a U.S.-Canadian science advisory panel that makes recommendations on EAB — began looking at possible ways to preserve ash as a component of North American forests and landscapes from the onset of the infestation, just in case strategies to stop the spread of EAB failed.

One course of action, Herms said, is to develop a resistant ash tree that can ward off attacks by the voracious beetle — whose larvae feed on the water- and nutrient-carrying tissue just under the bark, starving the tree to death in two to five years. This strategy has been employed by researchers in the cases of chestnut and elm, producing hybrids that are disease-resistant and still carry characteristics of the native trees.

"Identification of resistant genotypes will be critical for reforestation, as well as for maintaining market demand for ash in the nursery industry," said Herms, who also conducts research on insecticide treatments to protect trees from EAB and other management tools to deal with the pest in the present.

In the search for an EAB-resistant ash tree, Herms has teamed up with Enrico Bonello, an OARDC and OSU Extension plant pathologist; David Smitley, a Michigan State University entomologist; Donald Cipollini, a biologist at Wright State University; and Jennifer Koch, a biologist with the U.S. Forest Service's laboratory in Delaware, Ohio.

This team first established an experimental planting in 2003 in Novi, Mich., which was inside the core of the EAB infestation at the time. They wanted to expose different species of native and Asian ashes to the insect to evaluate their resistance to EAB, identify possible mechanisms of resistance, and determine the effects of drought and other stressors on susceptibility to the invasive pest. The planting included natives such as white ash and green ash; Manchurian ash (with which EAB shares an evolutionary history in Asia); and Northern Treasure ash — a hybrid between native black ash and Manchurian ash.

"Our working hypothesis was that the Asian ash would be the most resistant because of natural defenses resulting from co-evolution with the insect over a long period of time, considering that in Asia EAB does not devastate its native hosts," Herms explained. "The native-Asian hybrid was included because it could provide insight into patterns of inheritance of resistance genes and facilitate their identification."

The hypothesis proved right. While native ashes and even the hybrid succumbed to EAB, most Manchurian ash was much more able to withstand the attack. But of course, the team's work was far from over.

As the metallic-green ash borer took over northwest Ohio, Herms, Bonello and collaborators set up additional research plantings in the Toledo area to refine their studies. The latest experimental plot was established last fall in Bowling Green, a city that in 2005 adopted a very proactive management plan to deal with the arrival of EAB and has been a key partner of the Ohio EAB Task Force in monitoring and outreach efforts.

David Bienemann, Bowling Green municipal arborist, was instrumental in securing land for the planting at the city's Water Pollution Control Plan site, and he has also provided labor and equipment to plant and water the 192 trees. OSU Extension personnel and some 25 volunteers assisted in the effort, too. Now, researchers will wait for EAB adults to emerge in the spring, mate, lay eggs and infest the newly planted trees with their hungry larvae. The experiment will go on for three years.

"We hope to be able to expose these trees to natural attack by EAB in the zone of infestation," Bonello said. "We need this so we can characterize host responses to the pest. We expect that the response of species that are known to be more resistant, such as Manchurian ash, will be different from the responses of susceptible native ash species, and that we'll be able to differentiate between the two. Then we'll concentrate on what's different and see if we can use those characters as markers of resistance."

When it comes to developing resistant trees, Bonello said, there are two different routes researchers can take, which are not mutually exclusive. One is to monitor a large number of trees within a species (say, green ash) and locate the ones that are naturally more resistant to the insect or disease. Those hardier trees could then be propagated vegetatively (that is, through techniques like grafting or via cuttings), just like an ornamental cultivar.

However, Bonello indicated, this approach is very labor intensive and time consuming, and would result in just a few usable ash genotypes, thus providing fertile ground for EAB to develop countermeasures to whatever makes those cultivated varieties resistant — effectively defeating the effort.

"A second, preferred approach, which we have adopted," Bonello continued, "is to look for markers of resistance, and eventually the genes that are associated with them, so that we can use them in screening programs that do not involve challenging all plants with the insect. Furthermore, once the genes are found, they can be used in targeted breeding programs that may involve hybridization of native ash with Asian ash, similarly to what has been done in the case of the American chestnut vis-a-vis chestnut blight."

Although the project is ongoing, Herms said the team has already made some important discoveries related to the biochemical basis of EAB resistance in Manchurian ash, as natural defense compounds have been isolated and identified. Based on preliminary results, Koch and colleagues at the U.S. Forest Service have begun projects to hybridize Asian and North American ashes — the first step in developing a resistant tree.

Still ahead, however, is more work to identify resistance genes and determine how they are regulated. But the hope of being able to develop a new North American ash tree that will save this species from possible extinction, Herms added, is worth the effort.

Writer:

Mauricio Espinoza
espinoza.15@osu.edu
(330) 202-3550

Source:

Dan Herms, Entomology
herms.2@osu.edu
(330) 202-3506

The emerald ash borer, a colorful beetle from Asia that has killed tens of millions of ash trees in seven U.S. states, was first reported in the U.S. in 2002. This month, forestry officials announced that the ash borer had been found within the city limits of Chicago. U. of I. Extension entomologist Phil Nixon talks about the infestation with News Bureau Life Sciences Editor Diana Yates.

A Chicago forester stated earlier this year that it was "only a matter of time" before the emerald ash borer was found in Chicago. That prediction proved to be true. Is it possible to stop this bug?

Probably not. It is likely to eventually eliminate ash trees in North America. How long that takes can be affected by people. Also, resistant trees may be developed. For chestnut blight and Dutch elm disease, it has taken about 50 years to develop trees that are apparently resistant. Recent developments in gene technology may speed that process by several decades.

What can people do to help stop – or at least slow – its spread?

The most important thing to reduce it and other potential serious tree pests is to not transport firewood more than 50 miles from where it is cut. It is likely that that's the way that emerald ash borer got into Illinois. There are insecticide applications to protect individual trees, but funds are insufficient to pay for the protection of forest or public-owned trees.

Can state officials require that an infested tree be removed?

Yes, but they are unlikely to do so. The emerald ash borer is too widespread already in Illinois to be eradicated with the options and funds currently available.

An Asiatic fungus wiped out billions of chestnut trees in the U.S. in the early 20th century. Is the ash destined to go the way of the American chestnut, or do researchers have some tricks up their sleeves for saving this species?

Work is currently being done to look for genes present in resistant Asian species of ash with the goal of cross-breeding or inserting these genes into North American ash species.

For more information on the emerald ash borer, visit the U. of I. Extension's Chicago Emerald Ash Borer Central.

Illinois cities will soon receive federal assistance in financing their emerald ash borer management and prevention activities, U.S. Sen. Dick Durbin (DIL) announced today on Chicago's IIT campus, the site of the most recent EAB discovery. The EAB Revolving Loan Fund, which Durbin authored, became law earlierthis week as part of the farm bill.

"Illinois has more than 131 million ash trees and more than 20 percent of the trees in the Chicago area are ash," said Durbin. "In the past two years, emerald ash borer has killed tens of millions of trees throughout the Midwest forcing communities to spend large sums of money to dispose of the dying trees and replant new trees. The revolving loan fund will help provide Illinois communities with the resources to address the current situation and avert a potentially devastating one. In the past few years, this insect has killed tens of millions of trees throughout the Midwest – we need to do everything we can to get ahead of this infestation spreading further in Illinois."

Durbin's EAB Revolving Loan Fund is designed to help municipalities defray the costs of invasive species management activities normally performed by the federal government. EAB management activities, for instance, include surveying trees, removing infested trees and replacing removed trees. The bill creates a low-interest revolving loan fund for communities for the purchase of capital equipment and replacement trees to perform duties on municipal government land within quarantine areas. Communities would have a 20-year window to repay the loan. The current federal program does not reimburse municipalities for expenses related to invasive species prevention.

In addition, the bill allows states to contract with local units of government to perform invasive species management duties. While states are able to contract with the U.S. Department of Agriculture, for cost-sharing assistance, the funding does not reach the municipal level.

Durbin, a member of the Senate Agriculture Appropriations Committee, has been actively involved in efforts to secure emergency assistance for dealing with EAB since it was first discovered in Illinois in June 2006. Since then, over $10 million in federal funding has been allocated for EAB efforts in Illinois and the funding for EAB management across the nation has drastically increased due to Senator Durbin's efforts.

"Federal funding will be a critical resource in Chicago to assist officials in their effort to minimize the infestation and maximize our ability to utilize urban ash trees. That is why I will continue to lead a bipartisan effort in Congress to stop the spread of this invasive species."

The Emerald Ash Borer, which is currently present in Cook County, DuPage County, Kane County, LaSalle County, and Will County, is a bright green beetle that kills trees by burrowing into their bark and destroying the trees' ability to bring water from the roots to upper branches. Infected trees usually begin to die within two to three years.

Senator Dick Durbin announced the establishment of a loan fund to aid communities in the fight against the Emerald Ash Borer.

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From National Public Radio: The Emerald Ash Borer is a species of beetle accidentally imported from China a decade ago. So far the beetle has killed over 25 million Ash trees in the Midwest. Attempts to save the trees have had no success. But now tree scientists think they may have hit on a solution: genetically engineering the native tree variety with DNA from a beetle-resistant variety.

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Dr. Dave Roberts with Michigan State University discovered the Emerald Ash Borer in Michigan in 2002. In the following video he describes Emerald Ash Borer symptoms and diagnosis.

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In an effort to meet the challenge that Emerald Ash Borer represents in Indiana, the EAB Education and Outreach Team at Purdue University has created the "Arrest That Pest" EAB curriculum guide. They hope through the curriculum to motivate young people to take ownership of the environment and understand the ecological and economic impact of the emerald ash borer.

The curriculum and activity guide will facilitate learning about insects and their place in the ecosystem, generally, and the Emerald Ash Borer and its taxonomy, pathology, and impact specifically.

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The Chicago Furniture Association will present a traveling exhibit from August-Spring 2009. The exhibit will feature furniture made from salvaged Ash Lumber.

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Illinois Natural History Survey staff have created a detailed model of the emerald ash borer, that comes with a booklet to educate the public how to identify this destructive exotic pest. The kit includes a12-inch-long model of the emerald ash borer on a 17 inch by 11 inch base. Each model is individually hand-cast in polyurethane resin from a mold derived from an actual specimen. Each model is meticulously hand-painted and comes with a base resembling ash bark with a beetle exit hole.

Price for the kit is $350 plus shipping and handling. Call 217-333-6835 for ordering information.

Three species of wasps collected from ash trees in China have the potential to save ash trees in North America.

On Thursday (June 19) Purdue University researchers, armed with permits from the Indiana Department of Natural Resources and the U.S. Department of Agriculture Animal Plant Health Inspection Service, will begin to release 200 of the first wasp species in an ash forest near Rousch Lake in Huntington.

These wasps lay their eggs into the eggs of emerald ash borers (EAB). As the wasps feed, grow and develop, they eventually kill the ash borer eggs.

"In China, these wasp species reduced EAB populations by 74 percent in ash trees that are native to North America," said Cliff Sadof, Purdue professor of entomology. "With more than 8 billion ash trees at risk, these wasps offer real hope for reducing the possibility of North American ash extinction."

Later in the summer two additional wasp species will be released in the same location. Both species feed on emerald ash borer larvae.

"Our study will determine whether the wasps are able to establish a population, overwinter and effectively control emerald ash borer in the state," Sadof said.

Michigan State University began the same study a year ago, and Ohio State University will begin its study this summer.

Beyond emerald ash borer, the wasps are known only to rarely attack related wood borers, but have been shown not to be harmful to humans or the environment.

"These small wasps have no stingers and are not aggressive toward humans," Sadof said. "In addition, laboratory studies show that they do not like to lay eggs inside the eggs of anything other than emerald ash borers. When given a choice, they avoid attacking all but the most closely related borer species that are known pests of oak and birch trees."

In the past, researchers have found success in fighting other invasive species with natural enemies.

"Overall, about one-third of the biological control efforts for invasive species have resulted in complete or substantial control of the target," said Steve Yaninek, head of Purdue's entomology department. "The other two-thirds had partial control, no measurable effects or the natural enemies never became established. Negative environmental effects have been rare."

But while researchers are optimistic about the study, Sadof said any control benefits could be a few years away.

"It's important for people to recognize that despite new developments in chemical and biological control, we still have a long way to go to protect our ash trees," he said. "It may take several years to get the wasps established in Indiana and even longer for them to build up numbers where they can kill enough of the borers to make a difference in the forest.

"For these reasons, it is critical for people to refrain from moving firewood and other ash products outside of quarantined areas."

Quarantined areas and more information about emerald ash borer is available online at http://www.entm.purdue.edu/EAB.

Questions regarding the biological control of emerald ash borer study should be directed to Sadof at (765) 494-5983, csadof@purdue.edu. This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

Collaborators on this project are Deborah McCullough, Michigan State University; Dan Herms, Ohio State University; Leah Bauer and Hou Ping Liu, U.S. Forest Service; and Tonghai Zhao, Chinese Academy of Forestry in Beijing.

Since 2002 the Chicago Department of Streets & Sanitation's Bureau of Forestry has been working closely with the Illinois Department of Agriculture and the United States Department of Agriculture to prepare for the arrival of the Emerald Ash Borer (EAB), an invasive species of beetle from Asia that destroys the Ash Trees that it nests in. The EAB was first spotted in the United States in 2002 in Ash Trees in Southeastern Michigan. On Thursday Morning the City confirmed that the EAB has arrived in Chicago.

Last Thursday, June 12, 2008, a beetle resembling the EAB was captured on Chicago's South Side in a tree at 29th and State Street. Since many beetles resemble this pest, it was sent off for confirmation. The City has since then confirmed it is indeed the Emerald Ash Borer and on Wednesday, June 18, 2008, Streets & Sanitation officials spotted another EAB emerging from a downed tree limb on the same site.

Streets & Sanitation Commissioner Michael J. Picardi, senior managers from the department's Bureau of Forestry, local officials, and representatives from the Federal and State department's of agriculture were on hand for the Thursday morning announcement.

"We have been working with our federal and state allies to implement an EAB Management plan designed to protect our urban forest while combating the spread of the EAB in our area." stated Commissioner Michael J. Picardi. "This promises to be a much tougher fight than we had with other invasive insects because the EAB is aggressive and Chicago has a large population of Ash Trees."

The host tree at 29th and State where Chicago's first EAB was found was also the first tree slated to be taken down in Chicago due to infestation by the EAB. City Forestry crews will also be surveying the immediate area to see if any other trees are infested and need to be addressed.

The City's broader game plan is to actively manage the EAB response through a multiple strategy approach. This will include a citywide survey of all Ash Trees over the next 12 weeks to identify which trees are infested and which aren't.

Any limbs determined to be hazardous will be immediately removed and our inspectors will continue to monitor these trees for accelerated decline. Any trees found to be dead or in accelerated decline will be removed and chipped.

Trees that are found to be in good shape and free from infestation might be determined to be good candidates to be saved through the use of an internal insecticide called "Tree-age" that has just recently been approved for use by the State of Illinois Department of Agriculture. Because the City must wait for the next dormant period to use the product, trees will not be able to be treated until September.

Streets & Sanitation's Bureau of Forestry has been preparing for the arrival of the EAB in Chicago since it was first discovered in 2002 by working closely with their State and Federal counterparts. In 2003 the City imposed a ban on the planting of Ash Trees in the public way. The City has also been using traps to detect the presence of the EAB and will expand the use of these traps to 114 locations throughout the city. An Emerald Ash Borer found in a trap could indicate a presence up to 1 mile away

The EAB is responsible for destroying over 20 million trees in Michigan, Ohio, Indiana, Illinois, Maryland, and Canada. Beetle larvae feed under the bark and outer sapwood of the ash tree, producing galleries that eventually kill branches and entire trees.

In Chicago, ash makes up around 19% of the City's street tree population or about 96,000 trees. When adding an estimated 500,000 ash trees from private property to the total, ash trees become one of the most common trees found in the City.

For More information on the Emerald Ash Borer residents can visit Streets & Sanitation's home page at www.cityofchicago.org/StreetsAndSan

The City of Naperville received confirmation from the United States Department of Agriculture's (USDA) Animal and Plant Health Inspection Services Wednesday of the presence of the Emerald Ash Borer in a portion of southwest Naperville. This is the first confirmed case of the Emerald Ash Borer in Naperville and Will County.

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