Emerald ash borer

By Ken Johnson

The Illinois Department of Agriculture sets out survey traps each year to monitor for emerald ash borer (EAB). During this year’s survey, EAB was detected in 10 new counties: Madison, Mercer, Jackson, Saline, Hamilton, Wayne, Clay, Jefferson, Washington and Bond. This brings the total number of counties that have been confirmed to have EAB to 60. EAB has not yet been found Calhoun, Cass, Greene, Morgan or Scott Counties.

With these new detections Illinois will no longer restrict the movement of any cut non-coniferous firewood within the state. “The survey results this year support deregulation with nearly 60 percent of our counties confirmed positive for EAB,” says Plant and Pesticide Specialist Supervisor Scott Schirmer. “Over the past decade, the regulations and quarantines have served their purpose to slow the rate of spread and afford people time to manage for this pest. However, there comes a time when the pest is too widespread to continue to regulate, and this is our time.”

Despite the state dropping their restrictions on the movement of firewood and ash material, Illinois will still remain part of the federal quarantine according to Acting Agriculture Director Warren Goetsch. “Illinois will remain part of a federal quarantine, meaning firewood or other ash related products cannot travel into a state that currently has regulations. I urge people to consider the potential impacts of their actions, in general, before they move items like firewood. We’ve witnessed the impacts EAB has had on our trees and budgets, and we want to prevent introduction and spread of other current and future invasive species.”

The current recommendation for treatment of ash trees remains the same. Ash trees do not need to be treated for EAB unless you live in a county where EAB has been detected or if EAB has been detected within 10-15 miles of your location. There are some areas of eastern Cass County that are within 15 miles of Petersburg where EAB has been detected.

EAB adults are 1/3 to 1/2 inch long and elongate, with metallic emerald wing covers and a bronze body. Larvae of the beetle will burrow into the bark of ash trees causing the trees to starve and eventually die. The larvae are creamy white and legless. Their bodies are flattened and have bell-shaped segments and will grow to be about 1 and 1/4 inches long.

EAB will begin by attacking the top of a tree. Trees infested with EAB can have a variety of different symptoms including: a thinning canopy and yellowing leaves, vertical bark splits and increased woodpecker activity. The presence of these symptoms doesn’t necessarily mean a tree is infested with EAB; many other factors can cause these symptoms. EAB adults will form D-shaped emergence holes in the bark of the trunk or branches and basal shoots. When the larvae feed they will produce serpentine galleries below the bark. When the bark of an infested tree is removed these winding tunnels can be seen.

Once EAB is present in an area, all of the ash trees will eventually be killed. Therefore you will need to decide whether or not you wish to try and save your ash trees. There are several things to consider: Is the tree healthy? Is it in a good location? Is it valuable to the landscape or you (sentimental value)? Do I want to spend the money? If you decide it is not worth saving your trees, you will need to have them removed.

If your trees are smaller than 15” diameter at breast (chest) height you can treat yourself, if they are larger you should consider having them treated professionally. Several pesticides are available that are effective in controlling EAB.

If you have any questions, or if you suspect that you have an infested ash tree contact the Morgan County Extension office at (217) 243-7424, or the Illinois Department of Agriculture at (217) 787-5476.

Ken Johnson

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