What is the Emerald Ash Borer?
The Emerald Ash Borer (Agrilus Planipennis Fairmaire) is a metallic green beetle native to Asia. The beetle is 1/2 inch long and 1/8 inch wide. The adult emerges from the bark between the months of May and July. The females lay numerous eggs in bark crevices. The eggs hatch in 7 to 10 days and larvae bore into the tree where they feed on the inner bark and phloem, creating winding galleries. Eventually this cuts off the flow of nutrients and water, causing visible signs of stress. Top die back, suckers on the truck of base of the tree, vertical splits in the bark, and 1/8 inch D-shaped emergence holes are all indications of a possible infestation. There are native borers that also cause ash problems, but the exit holes are larger; they are 1/4 inch and round or oval.
The good news is the Emerald Ash Borer (EAB) will only attack ash trees. The borer poses no threat to people. EAB will attack healthy trees and can be very difficult to detect. Although treatment options are available, neither the United States Department of Agriculture (U.S.D.A.) nor the Illinois Department of Agriculture (I.D.A.) currently recommend preventable pesticidal treatments. The treatments are very costly, require yearly reapplication, and have not been very successful.
Since the EAB flies only short distances, the most likely cause of its rapid expansion is the movement of firewood, ash logs, brush, and nursery stock. Purchase only local firewood during the winter months. EAB larvae and adults can live on logs left through the spring.
The U.S.D.A. has quarantined the entire state of Illinois.
What is the Village doing about EAB?
The Village of Palatine has removed ash species from its approved street tree list and has not planted any ash species on the parkway since we became aware of the pest in 2002. Even so, roughly 20% of our parkway tree population is ash. Some areas of Palatine are monocultured with mainly green ash. Monoculturing was a past practice of planting only one species of tree on the parkway in a given area. This is the reason Palatine has been diversifying species selection for the past 30 years.
In the summer of 2009, the Village of Palatine had a positive confirmation of EAB in the Winston Park area. The Village’s Forestry Division has been working closely with the Illinois Department of Agriculture (I.D.A.) to detect and try to contain this pest. The evidence we have seen to this point leads us to believe EAB has been active in Palatine since at least 2008.
As EAB has spread across Palatine, the efforts of the Forestry Division to remove infested trees have been seen in many neighborhoods. Initially, the Village focused their removal efforts in areas where ash tree populations were very high. However, our arborists are finding high levels of EAB infestation in all neighborhoods with ash trees in the Village. Forestry Division crews and Village contractors anticipate needing to remove approximately 800 ash trees in 2013. These trees will be replaced with a variety of native and hardy trees to improve diversity of our urban forest.
Village arborists have seen a correlation between EAB infestation and woodpecker feeding. The woodpeckers remove flakes of bark in their search for EAB larvae. This is noticeable from ground level and helps to determine trees that will need to be removed. Trees to be removed will be marked with a red ‘X’ and residents will be notified of parkway tree removals by letter.
While the Village is not using chemicals treatments, private owners may elect to do so to prolong the life of parkway ash trees at their own expense and provided they complete documentation with the Village. If you are interested in coordinating this treatment on parkway trees adjacent to your home at your cost, please fill out a Permit Application and submit it to the Department of Public Works at 148 W. Illinois Avenue, Palatine, IL 60067.
The Village has been fortunate enough to receive over $35,000 in grants over the past several years to help manage costs of replacing the removed ash trees. In 2016, the Village spent approximately $275,000 to address removal and replacement of infested ash trees. As of 2017, the Forestry Division is in the final stages of removing and replacing ash trees. There are approximately 100 parkway ash trees remaining and they will be removed as they begin to show signs of infestation.
A recent review in our management of the infestation reinforced the timely removal of declining and dead ash trees. Planting diverse varieties of replacement trees in right-of-way areas will remain the focus of the Village.
If you have an ash tree on your parkway that is declining or dead, contact the Department of Public Works at (847) 705-5200.
Illinois Department of Agriculture's EAB Website