Spring Means Treatment Time For Emerald Ash Borer

May 20, 2014

There's still time to apply spring treatments against the emerald ash borer.  Colder temperatures slowed the development of ash trees so far this year.

The adult emerald ash borer emerges in mid to late May. Soon after, females lay numerous eggs on the trunk and branches of the ash tree. Peak emergence is in late June.

Scott Schirmer with the Illinois Department of Agriculture says since the beetles first appeared in Illinois in 2006 in Kane County, municipalities and homeowners have tried a variety of practices to get rid of them. Officials have also spent thousands of dollars to do so. 

He says it's difficult to prepare for the devastation associated with the insect.

"A way to look at it is that it is a natural disaster when it comes to ash trees. It's something that, 15 years ago, nobody saw it coming, so you couldn't prepare for it or budget for it like you would if your were re-paving a road or building a bridge."

University of Illinois Extension: Facts About the Emerald Ash Borer

Schirmer says the Department of Agriculture has been working with communities to determine how best to slow the spread of the insect, but he says total eradication has proven to be a failure. He says each community should take an inventory of their trees to keep costs in control:

"You can't run a car dealership if you don't know how many cars you have on the lot or how many you have sold or how many are coming in. You can't manage the emerald ash borer unless you know how many ash trees you have." -Scott Schirmer, Illinois Dept. of Agriculture

Northern Illinois has been hardest hit in the state, which remains under a quarantine for the emerald ash borer. That means there are limitations to moving firewood.

Rockford crews will treat several hundred ash trees this year as the city approaches its second cycle since officials spotted emerald ash borers in 2011. Mark Stockman heads Rockford's street division. He estimates $15,000 to $25,000 could be spent on pesticides this year. Stockman says proactive measures will be taken in determining the condition of the trees. This could mean the removal of some trees that are not able to be treated due to over infestation. 

According to the city of Rockford, the Ash species is approximately 15% of the 70,000 street tree population. It is also estimated another 110,000 Ash trees are on private property.

LEARN MORE: City of Sterling Ash Trees & Emerald Ash Borer Management Information (includes breakdown of trees and costs to treat.)

Scott Schirmer with the Illinois Department of Agriculture says the agency tries to help communities collaborate on best practices to combat the Ash Borer.

In Naperville, Ash trees are the most numerous species in the city’s parkway tree inventory, representing about 27 percent of the City's parkway tree inventory. 

Treatment Options

Naperville, for example, began its 3rd year of comprehensive treatment. Licensed contractors will utilize three types of treatments for the City's estimated 15,000 parkway ash trees. 

  • imidacloprid

The City will be using this treatment for most trees that are less than 18 inches in diameter. This annual treatment is applied as a soil injection around the base of the tree.

  • emamectin benzoate

Used for larger trees, this treatment consists of a chemical application that is injected directly into the tree and lasts for two years.

  • dinotefuran

A limited number of trees will be treated with Safari. This product is reapplied every year.