Tree Diseases and Insects

Anthracnose Anthracnose on maple

Unusually wet springs cause a disease called anthracnose.  It is most common on maples in Skokie, but it can infect other types of trees such as sycamore and oak.  More information can be found here.  Treatment is too late by the time you see the damage and it is rarely necessary.  You can help limit the spread for next year by raking up diseased leaves and placing them in yard waste bags, or by raking the leaves to the curb for pick up in fall.  There is no need to call the Village Forester for an inspection for anthracnose.

Dutch Elm Disease

Dutch Elm Disease (DED) is an aggressive fungal pathogen that kills trees. The fungus is spread from tree to tree by elm beetles.  Unfortunately, the disease is still active in Skokie because there are still over 300 susceptible parkway elms. The Forestry Division offers a 50/50 cost share fungicide treatment program for parkway elms to help control the disease. Residents who have an American elm are eligible to participate in this program. The treatment consists of injecting a liquid fungicide into the water-conducting tissue of the tree. It has a very good success rate in preventing DED infection from the feeding of elm bark beetles for up to three years. After three years, the tree must be retreated for continued protection from DED. Residents with a private elm may contact the Village’s contractor to have their tree treated for the same cost per diameter inch.

Emerald Ash Borer

In April 2007, the Illinois Department of Agriculture (IDOA) confirmed the presence of the emerald ash borer in a tree in Skokie. The metallic green beetle is small and will fit on a dime.  The larvae tunnel underneath the bark of ash trees and disrupt water transpiration within the tree.  Skokie had approximately 3,000 ash trees at the time, however, only a few hundred ash trees remain.

Learn more detailed information about the Emerald Ash Borer.