Diseases and Invasive Species

Emerald Ash Borer

Emerald Ash Borer

The Emerald Ash Borer (EAB) is a real threat to the ash tree population in Urbana. The City began progressive management/removal of public ash trees in 2008 after identifying 606 standing ash trees. In February 2018, that number is down to 68 ash trees with 40 of those treated by the City and/or residents. Ash trees removed from city parkways are replaced at no cost and residents are notified by letter. All of the treatments the city is using for EAB prevention are with injectable treatments. About 50% of the injected trees are being treated with Treeage while the remaining are receiving a new treatment called Brandt enTREE EB, a new technology that uses low pressure micro injections to treat the tree’s vascular system.

There are also an estimated 500 ash trees on private property and the City is actively seeking and working with tree owners to treat sufficiently healthy ash trees for potential treatment. If City arbor personnel spot an infected ash tree on private property, a bright green door-hanger is placed on the residence with further instructions. The City Arborist is encouraging property owners with ash trees to be proactive and take a look at their tree’s condition. Treatment can only save ash trees in the early stages of infestation. In addition, dead and mostly dead ash trees are more expensive to remove due to the extra difficulty of safely removing brittle limbs.

By City ordinance, an infected ash tree is a public nuisance and requires removal, however, if the ash tree is relatively healthy and no more than 30% defoliated, it may be treatable. The City offered assistance in 2017 called the Emerald Ash Borer Assessment and Treatment program (EABAT), which is to assist residents with identifying and managing infected ash trees on private property. If the tree qualifies, a member of the City’s arbor team will treat the infected tree on private property with the tree owner paying for the cost of the treatment. If 40 - 50% of the tree’s canopy is defoliated, the tree will not qualify for the program. It is recommended that infested ash trees be removed before they are entirely dead to save cost. A limited amount of chemical remains for 2018 and program candidates will be on a first come first serve basis.

If you are interested in participating in Urbana’s EABAT program, complete the application and mail it to the City Arborist.

The State of Illinois' Department of Agriculture (IDOA) no longer has regulations or restrictions in place for moving regulated ash materials. This also means that there is no longer a quarantine within Illinois. Current USDA EAB Detection Map

For more information about EAB, firewood regulations and compliance agreements, go to:

Learn more about EAB with these resources.
Ash Tree Canopy Thinning
Ash Tree Identification Guide
Selecting Ash Trees for Treatment

Please help us in our efforts to stop the disease from spreading and to preserve as many ash trees as possible. If you suspect EAB in a neighborhood tree, please contact City Arborist Kevin Sanderson at 384-2339.

Bacterial Leaf Scorch Disease

BLSBacterial Leaf Scorch (BLS) is a disease that affects the water and nutrient conducting tissues of trees. Locally, it is most common in red and pin oaks. This group includes as many as 800 trees on Urbana public property. BLS may also affect elm, sycamore, London plane, sweet gum, hackberry, ginkgo and maple trees.

City arbor staff has already detected BLS in Urbana’s State Street area where a percentage of red and pin oaks are showing signs of extensive dieback. Unfortunately, the disease cannot be cured. Residents are encouraged to assist in trying to manage the disease by:

  • watering during dry summer months
  • minimizing root disturbance by not planting flowers or digging around the tree
  • mulching the tree

Symptoms first appear on leaves in early to mid-summer and worsen as the season progresses mimicking drought or heat stress. Affected leaves may turn a yellow-green and then brown, usually from the outside of the leaf inwards. BLS usually begins with older leaves and spreads outward to leaves toward the branch tip.

If you suspect a tree has BLS and would like positive identification, you can take a portion of the branch with the symptoms to the U of I Plant Clinic after Labor Day. There is a $25 fee for analysis.

Learn more about BLS:

University of Illinois Extension Home, Yard and Garden Newsletter
University of Illinois Plant Clinic

Please help us in our efforts to stop this disease from spreading and destroying Urbana’s oak trees.

- Last Modified -October 1, 2021 - 1:34pm
- Author - admin