Emerald Ash Borer discovered in Evanston
7/21/06 - Illinois Department of Agriculture, City government, working to implement response plan and encourage public support
The Illinois Department of Agriculture (IDOA) today confirmed the Emerald Ash Borer (EAB) has been located in Evanston. The infestation was discovered by a City of Evanston Parks/Forestry Division employee while assisting in an extensive survey initiated as a result of an infestation in Wilmette. Beetles were found in seven trees located in Lovelace Park, located at Gross Point Road at Thayer Street in the far northwest area of Evanston. In addition, the Emerald Ash Borer was discovered in a tree on private property on the east side of Gross Point Rd. at Thayer St.
EAB is a destructive, non-native pest that feasts on ash trees. The first case of EAB was detected in June in Kane County and the EAB was found in Wilmette a week ago. A quarantine zone has been put in place around 51 square miles of Kane County to contain the spread. Once the survey in Cook County is complete, the quarantine will be amended to reflect the damage and contain the spread.
“The initial EAB find in Wilmette reflected 16 infested trees within a 5 block area,” IDOA Division Manager of Natural Resources Warren Goetsch said. “As the survey continues we have now found 30 trees within 2 communities all within a ¾ mile radius of the original detection. At this point we don’t know how much farther the infestation exists but we can’t stress enough how important community participation is in fighting the battle against the Emerald Ash Borer.”
“Evanston staff will promptly respond to all suspected sightings of the EAB,” said Douglas J. Gaynor, Director of the City of Evanston’s Parks/Forestry and Recreation Department. “Residents are learning to recognize ash trees and more of them now realize that the EAB is smaller than a penny. We expect the number of false sightings to decrease as more people become educated.”
Large posters with color photos and EAB information packets are on display at Evanston libraries, community centers and the Civic Center. In addition, residents are encouraged to visit www.emeraldashborer.info to view photographs of the insect and learn more about the EAB’s life cycle.
“The good news is residents and interest groups are on the lookout. The faster we can detect and respond to a positive case, the better chance we have of isolating and containing the pest,” said Mark Younger, the City of Evanston’s Arborist.
The Emerald Ash Borer is a small, metallic-green beetle native to Asia. Its larvae burrow into the bark of ash trees, causing the trees to starve and eventually die. While the beetle does not pose any direct risk to public health, it does threaten the tree population. Since the Emerald Ash Borer was first confirmed in the Midwest in the summer of 2002, more than 20 million ash trees have died.
Evanston has 4,059 ash trees on its parkway and in its parks, which is about 12% of the City’s 33,000 public trees. Additionally, there are thousands of ash trees on private property in Evanston. Ash trees were widely planted in the city and in much of northeast Illinois because they are fairly inexpensive and generally quite tolerant of soils and climate in this area.
In 1999, the City of Evanston created a policy whereby any tree species that made up more than 10% of the overall population would no longer be planted on public property. This means the City has not planted any new ash trees since 1999. This effort to further diversify the overall tree population was specifically aimed to minimize the effects of an infestation.
Evanston residents with questions can call the Evanston Parks/Forestry Division at 847-866-2912 or send an email to forestry@cityofevanston.org.
In order to increase public awareness of this problem, the City offers the following information:
Where did the Emerald Ash Borer Come from?
The Emerald Ash Borer is an exotic insect pest from Asia. It was first discovered in the U.S. in 2002 in southeast Michigan. Since that time, this tree destroyer has also been detected in Indiana, Ohio, Maryland and Ontario, Canada.
Prior to its discovery in the U.S., the Emerald Ash Borer was found primarily in Korea, China, Japan and other East Asian countries. In the U.S. thus far, this pest has been known to attack all native ash trees, specifically White, Green and Blue ash; it does not attack Mountain ash and likely not European ash.
How do I know if my tree is an Ash?
Ash trees have several green leaflets per leaf stem, usually 7. The leaflets are located directly across from each other with one leaflet on the end. The leaf shape is “lanceolate,” which means they are much longer than wide, broader below the middle and tapering to the top. If the tree in question is on public right-of-way (parkway) in Evanston, its species may be verified by a call to the Parks/Forestry Division at (847) 866-2912, since all such trees have been inventoried.
What is the EAB's lifecycle?
The Emerald Ash Borer adult is a dark metallic green beetle only about 1/2” in length and 1/8” in width. Adults are only present from mid-May to late June, when they feed on the leaves of ash trees. Soon after they emerge, the adults lay eggs on the trunk and branches of ash trees. After about a week the eggs hatch into larvae which then bore into the tree. It is this larval stage that does the major damage. Larvae are creamy white in color, can grow up to an inch long and are found under the bark of the trees. These larvae tunnel and feed, creating S-shaped galleries. This tunneling cuts off the food and water supply to the tree, causing it to die. Later in the year, the larvae pupate and overwinter under the bark. New adults emerge the following May. Their emergence holes are very small (only 1/8”) D-shaped holes and can occur just about anywhere throughout the tree.
What are the symptoms?
Infestation of EAB can be difficult to detect until the branches of the tree start to die. Usually the leaves on the upper third of a tree will start to thin, and the branches will begin to die back. This is usually followed by a large number of shoots or branches arising below the dead portions of the trunk. Additional evidence of infestation includes the tiny D-shaped exit holes on the branches and the trunk. Distinct S-shaped larval feeding tunnels may also be apparent under the bark.
How does EAB Spread?
It is thought that the beetle arrived in the U.S. from Asia in the early 90s, but it was not positively identified until 2002. It is believed that the larvae hitched a ride across the borders traveling in wooden pallets. Once arriving in the United States the insects emerged as adult beetles and the cycle of devastation began. The EAB is an excellent flier and can travel fairly far distances in search of food and egg-laying sites in ash trees. Additionally, pockets of EAB outbreaks have been linked to the movement of firewood and ash tree nursery stock out of infested areas.
Who is fighting the beetle?
Because this insect has such great potential to decimate both forests and urban tree populations, national and state agencies are working together to stop the spread of EAB. These agencies include the USDA Forest Service, APHIS (Animal and Plant Health Inspection Service), and the various state Departments of Agriculture. In Illinois the lead agency is the Illinois Department of Agriculture (1-800-641-3934). Unfortunately, very little information on the beetle is available from its native region, and limited control management recommendations exist to date. Research on various insecticides is being conducted, and some are quite promising. However in new infestations, the goal must be complete eradication of every single Emerald Ash Borer. Thus in these areas, infested trees as well as surrounding healthy trees are declared a “Public Nuisance” and removal of these trees is required by law.
Fortunately in Illinois, a wide variety of organizations and agencies concerned about our urban and forest trees have had an “Illinois Emerald Ash Borer Readiness Plan” in place since 2004. This plan was compiled by the Morton Arboretum’s Community Trees Advocate and it outlines a plan for a coordinated and prompt response by all involved parties.
Steps residents can take
The City of Evanston Parks/Forestry Division believes that public education about EAB offers the best hope for both preventing its spread throughout the region. We are asking ask property owners to. . .
- HELP MONITOR AND REPORT - Learn about EAB, check your ash trees for the pest and call us at (847) 866-2912 if you believe you have found either the insect or an infested ash tree. We’ll respond promptly to all such calls.
- STAY INFORMED AND FOLLOW DIRECTIVES FROM THE ILLINOIS DEPARTMENT OF AGRICULTURE- Check for periodic updates at these websites: www.cityofevanston.org, www.agr.state.il.us and www.emeraldashborer.info.
- REFUSE TO MOVE FIREWOOD OR PURCHASE ASH WOOD - Use only local firewood (even when traveling), and burn the wood on site or leave it when you move on. Especially, don’t bring firewood or logs from other states, or any areas that may become quarantined in Illinois, to Evanston. Do not purchase any firewood containing ash wood until further notice.
- CARE FOR ASH TREES- Call the Parks/Forestry Division if a public ash tree seems sick or needs maintenance. Care for private trees routinely, using ISA-certified arborists when hiring tree care companies.
- PLANT FOR DIVERSITY- Do not plant ash trees. Plant underutilized tree species instead.