Tree Pests & Diseases

Trees throughout the Midwest are subject to countless insect pests and diseases. Learn how to recognize signs of infestation or infection, ways to prevent attacks on your trees, and how to minimize damage when destructive insects and deadly diseases reach your yard.

A dense cluster of hairy caterpillars with white and orange stripes feeds on a silk mat spun against tree bark.
What Are These Webs, Holes, and Spots on My Trees in Johnson County?
You know your trees well enough to notice when something looks different. Maybe you don’t remember those webs ...
White powdery mildew coating the upper surface of oak leaves on a Parkville tree in August.
What’s Wrong With My Tree? Common Late-Summer Tree Problems in Parkville
A tree can look healthy through early summer and start showing some strange symptoms by late summer: webs ...
Ripe red-orange crabapple fruit and green leaves on a West Des Moines crabapple tree.
Why Is My West Des Moines Crabapple Losing Leaves in Summer?
A crabapple that starts summer covered in leaves can look surprisingly bare by the end of it. Across ...
Dead oak with a bare, brittle canopy standing above green trees in late summer.
Why Is My Cedar Rapids Tree Wilting and Turning Brown This Summer?
A tree that looked healthy at the beginning of summer can look very different by the end of ...
Fall webworm nest wrapped around branch tips of a mature tree in late summer.
What Are Those White Webs on Your Tree Branches?
One day your tree looks perfectly healthy. The next, white webs seem to have appeared out of nowhere. ...
Professional identification helps distinguish eastern tent caterpillars from fall webworms so the right management approach can be recommended.
How to Identify Bagworms, Webworms, and Spider Nests on Your Norman Trees
Hanging bags, white webs, and spider silk all start appearing on Norman trees during the summer, but they ...
Fall webworm silk nests wrap the branch tips of a backyard tree in the east Des Moines metro.
Why Are There Webs in My Tree in East Polk County?
In late summer across the east Des Moines metro, from Pleasant Hill and Altoona out through east Polk ...
Mature elm with scattered branches of brown, wilting leaves thinning its canopy, an early Dutch elm disease symptom.
How Do You Spot Dutch Elm Disease Symptoms on a Quad Cities Elm?
Across the Quad Cities, on either side of the river, mature elms still shade backyards and parkways. If ...
Close-up of an adult Japanese beetle with a metallic-green body and coppery-brown wing covers on a leaf.
Why Are Japanese Beetles Eating My Tree Leaves in Cedar Rapids?
Earlier this month, Japanese beetles reached peak activity across Cedar Rapids and the Iowa City corridor—swarming the canopies ...
Pin oak with pale yellow, iron-chlorotic leaves beside a healthy deep-green maple in a western Des Moines front yard.
Why Are My Pin Oak Leaves Turning Yellow in Des Moines?
Yellow leaves on a pin oak can be more than a cosmetic issue. What begins as mild discoloration ...