How Can Insects Harm Trees In Portland Yards?

Serving Families Throughout Portland & the Pacific Northwest

Insects, spiders, and other arthropods make up the largest animal species on the planet. While insects are small, they can be destructive to trees and shrubs in your Portland yard.

They damage trees by leaving their harmful bacteria behind, which can spoil the tree’s branches or leaves and some even chew holes in the branches.

3 types that affect trees

We’ll describe the damage these insects do and signs to look for to determine if your trees are infected.

  • Chewing insects
  • Boring insects
  • Sucking insects


Most chewing insects feed on the leaves (foliage) of a tree while others attack the fruit.  Caterpillars and beetles are the most common of the chewing insects and make up the largest portion of chewing troublemakers.

Usually trees bounce back from an attack though repeated infestations can weaken a tree and kill it by starving it of energy.  This happens because trees need their leaves (foliage) for photosynthesis, the process by which it provides nutrients or fuel for itself.


Boring or tunneling insects are the most destructive as they bore into the stem, roots, or twigs and feed on the vascular tissues of the tree.  Some lay eggs, which hatch, and the larvae burrow even deeper blocking off the water-conducting tissues of the tree.

If the infestation is serious, upper leaves are starved of nutrients and moisture.  If left untreated, it often resulting in the tree dying.


  • Entry & exit holes in the bark
  • Small mounds of sawdust at the base
  • Sections of the crown wilting & dying

It’s good practice to inspect your trees periodically so you can catch any infestation early as that’s when treatment is quicker and more effective.


Aptly named, these insects do damage by sucking out the liquid from leaves and twigs.  Many are mostly immobile and live on the outside of a branch.  They form a hard, protective outer coating while they feed on the plant juices in the twig.

They often excrete a sweet, sticky substance called honeydew, which contains the unprocessed plant material.  Honeydew can cause sooty mold to form on leaves and is a sure sign that you have a problem.


An example of a sucking insect is the tiny 1/4″ long Lace bug. They attack rhododendrons, azaleas and Indian plum, a native shrub common to the Pacific NW.  Their name comes from the lace-like network of veins on their translucent wings.

Adults and nymphs suck plant sap from the underside of leaves causing it to appear dotted with tiny white spots.  After time, the small spots merge and the leaves turn yellow.  There will also be black tar (fecal) spots on the lower leaf surface.

A heavily infested plant becomes unsightly and its vitality is reduced. Severe infestations may cause premature leaf drop, and small shrubs may even die.


If you have trees or shrubs in your yard that look unhealthy or exhibit any of the signs mentioned, contact General Tree Service for a consultation.  As with any disease or insect infestation, it’s best to catch it early as that’s when treatment is most successful.

The post How Can Insects Harm Trees In Portland Yards? appeared first on General Tree Service.

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