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City Parks Department Updates Plan to Combat Emerald Ash Borer

Emerald Ash Borer

Jan. 30, 2015

For more information, please contact:

Mick Renneisen, Administrator, City of Bloomington

Parks and Recreation Department, 812.349.3700 or

City Parks Department Updating Plan to Combat Emerald Ash Borer

Bloomington, Ind. - The City of Bloomington Parks and Recreation Department is working with the Bloomington Tree Commission to revise their management plan for ash trees in the city's urban forest. The invasive emerald ash borer (EAB) made its way to Bloomington late in 2012, and has continued to spread, and kill ash trees, throughout the city.

The EAB beetle, a native of Asia, burrows into the bark of ash trees during its larval stage and destroys the tree's vascular system. Most trees infested with the emerald ash borer die within two years.

Because the EAB eats ash trees exclusively, the city's urban forestry program is focusing its attention on about 700 ash trees currently located along city streets and in public rights of way.

The City of Bloomington is considering a combination of three options for the ash trees in the urban forest: Treat ash trees with an insecticide to prevent an infestation; leave ash trees untreated, and allow the EAB to eventually find and kill them; or remove the ash trees.

In order for insecticide treatments (the preferred method is injection directly into the tree) to be effective, they must be made during a six-week window in the spring when the EAB larvae hatch and begin to feed. Current urban forestry best practices guidelines call for treatments every other year, for the life of the tree, to effectively protect the tree from EAB.

Since budget constraints do not permit the chemical treatment of the hundreds of remaining ash trees on city-owned property, Bloomington Parks and Recreation is embarking on an ash identification and assessment campaign to measure and evaluate the health of the trees, and to use that information to determine what approach to take with each individual tree.

Urban forester Lee Huss will spend most of the month of February marking and assessing the city's ash trees. Each publicly owned ash tree along city streets and in rights of way will be marked with a dot of purple paint. Huss will measure each tree, evaluate its overall health, and note whether there are indications of EAB, such as branch dieback or woodpecker activity. When each tree has been evaluated, parks and recreation department staff and the Bloomington Tree Commission will have updated information to formulate a comprehensive and responsible plan to save the ash trees that are fiscally and reasonably possible to save, and to remove those trees that are not.

Bloomington Parks and Recreation began strategically removing ash trees, especially trees that were small or in poor health, when the EAB appeared in Bloomington in 2012. The city has not planted any new ash trees on public land since 2003.

"We have a responsibility to minimize the spread of EAB as much as possible by removing their food source, but we also have a responsibility to protect and nurture our urban trees," said Mick Renneisen, Administrator for the Bloomington Parks and Recreation Department. "Our revised EAB management plan will guide the continued wise use of resources, and allow us the flexibility to respond to EAB outbreaks, or other tree-related issues, in different areas of the city."

EAB most likely traveled to Bloomington in firewood that was infected with the larvae. Monroe County is a quarantined county, as designated by the Indiana Department of Natural Resources, and firewood without a federal or state compliance stamp cannot be transported out of the county. Ash trees removed from city streets will be kept within the quarantined area.

The city's urban forester will evaluate only those trees that are publicly owned, but noted that landowners with ash trees have the same three options as the city does for treating, leaving, or removing. Private landowners can get help identifying ash trees and information about the long-term commitment and cost for treating their own as trees at or at

Landowners may also contact Amy Thompson, Extension Educator, Purdue Cooperative Extension Service, at (812) 349-2575 for more information about EAB.