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Encyclopedia Dubuque


"Encyclopedia Dubuque is the online authority for all things Dubuque, written by the people who know the city best.”
Marshall Cohen—researcher and producer, CNN

Affiliated with the Local History Network of the State Historical Society of Iowa, and the Iowa Museum Association.


From Encyclopedia Dubuque
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Photo courtesy: Telegraph Herald
EMERALD ASH BORER. Emerald ash borer is the latest of a number of infestations of invasive species or diseases to spread across the United States and nearly wipe out an entire genus of tree. In the twentieth century, the chestnut blight, a fungus that originated in Asia, wiped out nearly all chestnut trees in the United States by 1940. DUTCH ELM DISEASE which originated in Asia wiped out thousands of elm trees including Dubuque's "Cathedral of Elms" along Rhomberg Avenue. (1) The emerald ash borer is a beetle native to northern Asia that was found in Michigan in 2002. It is believed the beetle was brought to this country on shipping crates or pallets through the Great Lakes. (2)

In December 2014, emerald ash borer (EAB) infestations had been confirmed in 18 Iowa counties and as close to Dubuque as Jo Daviess County, Illinois. While infestations of the destructive invasive species had been seen in Dubuque, city staff were developing plans to deal with that eventual discovery and the short-and long-term impacts that would accompany it. (3)

The Dubuque City Council considered at its January 5, 2015 meeting the adoption of a recommended Emerald Ash Borer Readiness Plan, developed by City of Dubuque Park Division Manager Steve Fehsal and City Forester Steve Pregler. The goal of the plan was to identify appropriate and effective actions to be taken in the event that the EAB was discovered within Dubuque’s city limits. These actions included prevention, detection, communication, and management activities to minimize the effects of EAB on the City’s ash tree population. (4)

Dubuque’s Park and Rcecreation Commission reviewed the EAB Readiness Plan at their December meeting and unanimously recommended its approval. The readiness plan also discussed plans to replace city-owned ash trees that were removed or lost. As budget and planting policy guidelines permited ash trees would be replaced with species appropriate to the site and increase overall species and age diversity of public trees. (5)

The EAB has a one-year life cycle, emerging between May and July. The EAB kills trees relatively quickly and affects North American ash whether healthy or stressed. The EAB deposits eggs on the surface or in cracks of ash tree bark and they hatch in seven to 10 days. The larvae feed on the tree’s inner bark and, within several weeks, this feeding creates S-shaped tunnels in the tree’s inner bark that wind back and forth, becoming progressively wider. This disrupts the tree’s ability to transport water and nutrients, eventually killing the tree. (6)

Adult EABs emerge from trees headfirst, creating very small (one-eighth inch diameter) D- shaped exit holes that leave minimal evidence of infestation until the tree’s canopy begins to die back. Affected trees quickly decline in the second growing season and are usually dead by the third season. (7)

Ash trees were a popular replacement tree following DUTCH ELM DISEASE in the 1960s; they were used heavily as a landscape tree throughout Dubuque. A preliminary ash tree survey of Dubuque identified approximately 1,750 city-owned ash trees including street trees, trees in parks and recreation areas, and trees on all other city-owned properties. The inventory did not include ash trees in wooded areas, along park wood lines, in undeveloped right of ways, or in roadside ditches and alleys. (8) The cost of removing an ash tree could range from $1,000 to $3,000 per tree. (9)

In September 2015, the Iowa Department of Agriculture announced that emerald ash borer had been found in Dubuque County, the 28th county in Iowa where EAB had been discovered. Larvae was discovered in the southern part of the county along with a location just south of the city limits. (10)

“Iowa now has seven counties bordering the Mississippi River that have turned up positive for EAB,” Mike Kintner, Iowa Department of Agriculture and Land Stewardship EAB and gypsy moth coordinator, said in a written statement. “Unfortunate as it is, I wouldn’t be surprised to see the remaining three counties declared positive within a year.” (11)

In 2014 Iowa had an estimated 55 million ash trees. While the borer posed a serious threat to the trees, it was not seen as having an important impact on the lumber business. Ash was not used in the building industry and while it was used for baseball bats, pool cues and the manufacture of oars, ash could be substituted with maple. (12)

In 2019 the removal of ash trees was seen throughout the city with pockets of high density in residential areas around STEPHEN HEMPSTEAD HIGH SCHOOL. Among the early signs of the disease were cracks in the bark, thinning of the upper canopy, S-shaped impressions in the wood, many woodpecker holes, and branches sprouting from the base. As the disease progressed, dead limbs snapped off creating potential safety hazards and financial liability for the city. As the number of trees needing removal increased, the city had only a crew of four men dedicated to tree removal--including those toppled by storms. For this reason, $45,000 was set aside for the 2019 fiscal year for tree removal with an estimate that the final bill in coming years could total $1.5 million. Disposal of the trees in 2019 was done through an agreement with Bill Miller & Sons Logging. (13)

It was not expected that the emerald ash borer would entirely wipe out the ash tree in America. As with the chestnut tree, a unique genetic type could save the species. Elm trees, for example, although drastically diminished, continued in 2019 to have more than 50 million of their species living in Iowa. Ash trees are also "aggressive germinators." This, however, could also mean that the specie would continually be faced with the borer which would find an endless amount of food. (14)



1. Krause, John, "Ashes to Ashes," Telegraph Herald, October 20, 2019, p. 1A

2. "Get Ahead of the Emerald Ash Borer," Julien's Journal, September 2014, p. 52

3. News Release. City of Dubuque, January 1, 1915 Online: http://www.cityofdubuque.org/newsreleases

4. Ibid.

5. Ibid.

6. Ibid.

6. Ibid.

8. Ibid.

9. Krause

10. Page, Eric. "Emerald Ash Borer Found in Dubuque County," September 1, 2015, KWWL.com. Online: http://www.kwwl.com/story/29936287/2015/09/01/emerald-ash-borer-found-in-dubuque-county

11. Ibid.

12. Towers, Lisa. "Emerald Ash Borer Formidable Foe to Ash Trees," Telegraph Herald, December 3, 2014, p. 59

13. Krause

14. Ibid.