Diseases & Pests

What's Killing My Tree

Did you know that most tree problems result from a combination of factors? Insects and diseases often get the blame for killing trees, but factors like drought or construction damage are most likely the primary cause of a tree's death. These primary factors weaken a tree's defenses, making it more susceptible to attack by secondary invaders like insect borers and wood-decaying fungi. 

In This Section

Invasive Tree Pests

Invasive tree pests are insects and diseases that are not native to Missouri. These pests can easily travel in firewood. You can help protect our forests by purchasing firewood where you plan to burn it.

Missouri Invasive Forest Pest Plan (pdf, 496 KB)

The Missouri Invasive Forest Pest Plan provides an overarching framework for a coordinated response in Missouri to invasive forest insects and diseases.  Roles and responsibilities of cooperating agencies and response actions common to most invasive forest pests are defined.

Oak Decline in Missouri

Large numbers of northern red, southern red, black and scarlet oaks are declining and dying in southern Missouri. Find out why, and learn what you can do about it.

Periodical Cicadas

Periodical cicadas live as nymphs for 13–17 years underground, and then emerge simultaneously to metamorphose into their adult form.

Related Content

Forest Health Alert: Japanese Beetles (pdf, 1 MB)

These insects can eat all the leaves off your tree. Learn what you can do to stop them.

Forest Health Alert: Oak Wilt (pdf, 2 MB)

This disease of oaks is easily spread in the spring. Learn to identify and prevent it.

Forest Health Alert: Hypoxylon Canker (pdf, 2 MB)

This disease of oaks and other hardwoods is common after drought. Learn to identify and respond to it.

Tree-Branch Flagging

Brown leaves appear on individual branches scattered throughout the tree crown. This condition of “branch flagging” can be caused by insects, diseases or weather-related injury.

Ice-Melter Damage

Learn how to treat salt-damaged trees and soil, and protect your plants where ice melters are used.

Forest Health News

Browse up-to-date bulletins on the causes of branch flagging, insect defoliators, exotic insect and disease pests, conifer problems and current disease issues.

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