Pests and other problems

Insect pests and diseases are among the greatest challenges to maintaining a thriving urban and community forest.

Many of the most severe problems are caused by invasive species-- insects, diseases, or even other plants that were brought from one location to another where they did not originate. Since local trees did not evolve alongside these organisms, they also did not evolve defenses against them.

Invasive species of insects that feed on trees, such as the emerald ash borer and the gypsy moth, and the viruses and bacteria that infest them, such as Dutch elm disease, can directly kill trees. Meanwhile, invasive species of plants can reproduce so rampantly that they out-compete more desirable trees for space, sunshine, water, and nutrients or prevent regeneration. These threats can indirectly kill trees.

The Morton Arboretum's Community Trees Program provides extensive outreach and information for governments, tree professionals, and property owners seeking to safeguard their trees or to cope with the impact of a devastating infestation.


Invasive Species Awareness Month

Each May is Invasive Species Awareness Month at the Arboretum and throughout Illinois. LEARN MORE


Emerald Ash Borer

The Community Trees Program provides specialized workshops for communities, private interest groups, and others. Staff frequently provide educational presentations and have free resources available by request. Learn more in our informational brochure for homeowners.


2016 Forest Health Highlights

This annual publication reviews the pests, pathogens and other concerns from the forest health perspective. The publication is prepared by Fredric Miller, PhD. D. IDNR Forest Health Specialist at The Morton Arboretum, Lisle, Illinois. Forest Health Highlights