Diseases and Invasive Species
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 affected by EAB. In 2017, that number is down to approximately 100, and the goal is to remove +/- 50 of those trees by the end of the year. Ash trees removed from city parkways are replaced at no cost and residents are notified by letter. The remaining 50% of public ash trees are being treated to protect them from EAB. A percentage of them are being treated with Treeage while others are receiving a new treatment called Brandt enTREE EB, which is a revolutionary 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 that can potentially be saved. 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. We are also encouraging property owners with ash trees to be proactive and take a look at their tree’s condition.
By City ordinance an infected ash tree is considered a public nuisance and requires removal, however, if the ash tree is relatively healthy and no more than 30% defoliated, it may qualify to be treated through the Emerald Ash Borer Assessment and Treatment program (EABAT), which was designed by City leaders 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, it’s probably beyond treatment and removal should be considered before the tree becomes brittle, more difficult/expensive to remove and starts to fall apart.
If you are interested in participating in Urbana’s EABAT program, complete the application and mail it to the City Arborist.
Learn more about EAB with these resources.
Pleas 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 Mike Brunk at 384-2393.
Bacterial Leaf Scorch Disease
Bacterial 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:
Please help us in our efforts to stop this disease from spreading and destroying Urbana’s oak trees.