Naperville treating trees against emerald ash borer

Beginning in early April, the city of Naperville will be continuing its multiyear treatment plan for all healthy ash trees in the city's parkways to reduce the effect of the emerald ash borer in the community.

If the city did not treat any of its parkway ash trees against the infestation, it is estimated that all of the parkway ash trees would be gone within five years.

In 2013, the city treated 12,865 trees. Following inspection, 91 percent of parkway ash trees were exhibiting only minor or no damage and will see continued treatment this year. Treatments are capable of sustaining, if not improving, ash trees not heavily damaged by the beetle. Nearly 80 percent of ash trees have sustained or improved their condition.

Licensed contractors will use three types of treatments for the city's 15,000 parkway ash trees:

• Xytect (imidacloprid): The city will use this treatment for most trees less than 18 inches in diameter. The treatment is applied as a soil injection annually around the base of the tree.

• TREE-äge® (emamectin benzoate): Used for larger trees, the treatment consists of a chemical application injected directly into the tree and lasts for two years.

• Safari (dinotefuran): A limited number of trees will be treated with Safari. The product is reapplied every year.

Homeowners with trees that receive treatment will be notified with a door hanger indicating what treatment has been used. Treatments are anticipated to be performed between April and June to protect the trees for this season. By treating the tree in early spring, the chemical moves up through the tree and is ingested by the beetle's larvae, which kills them and protects the tree from serious damage.

Badly infested parkway ash trees will be removed. Residents will be contacted if a tree in their parkway needs to be removed.

Residents can visit the city's website at naperville.il.us/eab.aspx to view an interactive map that will allow them to track treatment progress of parkway trees in their area. Residents can find out the size of their parkway trees and what treatment, if any, has been completed.

"Should homeowners wish to attempt to save their ash trees, treating them now is essential," city Forester Jack Mitz said. "If homeowners have questions or concerns, they should consult with an arborist to help assess if the tree they have is indeed an ash tree and if they want to attempt to save it."

For residents with ash trees on their private property, various treatment options are available. One should weigh the treatment expense with the value the trees provide in energy savings, property value enhancement and numerous environmental benefits against the removal and replacement costs if the trees are left untreated. A list of qualified vendors is available at naperville.il.us/eab.aspx.

Since 2008 when the emerald ash borer first was discovered in Naperville, the Department of Public Works has been implementing a containment strategy that consists of removing all badly infested ash trees; inspecting and treating parkway ash trees; and coordinating efforts with the state of Illinois, townships and the Naperville Park District. The city's Forestry Division works with 11 certified arborists who are trained to look for signs of the beetle's presence.

Information about the emerald ash borer, including symptoms of infestation and treatment options, is available at naperville.il.us/eab.aspx.