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Current Tree Health Issues

Tree diseases and pests vary tremendously from region to region, and what’s ailing a tree is often difficult to diagnose. Below you will find some basic information about what may be affecting your tree’s health. (Please consider contacting your local Cooperative Extension Service or certified arborist for further assistance.)

For information about more tree health issues, please visit the Pests and Diseases section of the USDA Animal and Plant Health Inspection Service website.


Jump to: Drought | Disease | Pests | Invasive Species | Improper Planting


Drought

One of the more common issues affecting trees across the country is drought. Lack of water can cause a wide range of issues including:

  • Leaf wilting
  • Leaf scorch
  • Stem dieback
  • Increased susceptibility to pests and diseases

To protect your trees from the effects of drought, start by choosing species that will grow well in your conditions and follow basic tree watering guidelines.


Disease

Diseases can vary greatly based on the type of tree and the region it grows in. Some of the more common diseases are listed below along with links for more detailed information.

  • Dogwood Anthracnose – affects flowering and Pacific dogwoods
  • Dutch Elm Disease – affects American elms, winged elms, September elms, slippery elms, rock elms and cedar elms to varying degrees
  • Eastern Filbert Blight – affects hazelnuts
  • Oak Wilt – affects many species of oaks
  • Pine Wilt – affects nonnative pines such as Austrian, Scots and Japanese red and black pines
  • Sudden Oak Death – fatally affects tanoaks, coast live oaks, Shreve’s oaks, California black oaks and canyon live oaks; also affects Douglasfirs, coast redwoods, madrones and many other trees
  • Thousand Cankers Disease – affects black walnuts

Pests

Just like diseases, tree-damaging pests to look out for depend on the type of tree and the region. Below is a list of some common pests you may be facing along with links for more detailed information.

  • Asian Longhorned Beetle – affects green ashes, paper birches, cedar elms, goldenraintrees, hackberries, horse chestnuts, katsuras, London planetrees, sugar maples, mimosas, mountain ashes, poplars and willows
  • Bark Beetles – affects a wide variety of trees depending on beetle type
  • Emerald Ash Borer – affects ash trees
  • Gypsy Moth – affects hundreds of species of plants, but oaks and aspens are most common
  • Hemlock Woolly Adelgid – affects both eastern (Canadian) and Carolina hemlock
  • Japanese Beetle – affects hundreds of species of plants
  • Periodical Cicada – occasionally affects small trees or shrubs

Invasive Species

Invasive species are plants, animals and pathogens not native to the region that are either currently or likely to cause harm. Find out more at the National Invasive Species Information Center.


Improper Planting

If a tree is not properly planted, its health could be compromised. One common mistake is planting the root flare (the point where the trunk begins to spread out as it meets the roots) too deep. This will cause a slow decline, ultimately killing the tree.

To learn more about proper planting depth and how to fix the problem, watch this Tree Planting Depth video.


Special note
Arborday.org is designed to provide non-biased information to the general public with no intended endorsement of specific products, companies, or services. It is important members follow the published recommendations of their own respective State Cooperative Extension Service when considering pesticide, insecticide, fungicide, and herbicide recommendations for the care of trees and shrubs. You may decide to seek an organic, Plant Health Care (PHC) or Integrated Pest Management (IPM) solution to your problem. Questions related to cultural practices and issues not specifically covered by Arborday.org should always be referred to your local Cooperative Extension office, Certified Arborist, or local Nursery Professional. Questions concerning commercial orchards or tree crops should be referred to your local Extension Service.