What’s Wrong With My Tree? Scale Insects

Scale Insects Are Common Tree & Shrub Pests

Scale insects are common pests to many trees and shrubs in North America. The scale includes both armored and soft varieties, including:

These insects are closely related to aphids and whiteflies, and all vary in size. The scales they produce can have the appearance of a reptile or fish scale or resemble an oyster shell or small mussel.

What Trees & Shrubs Are Affected By Scale Insects?

All trees and shrubs can be affected by scale, though some are more resilient than others. These include:

  • Oak
  • Dogwood
  • Ash
  • Pine
  • Spruce
  • Maple
  • Magnolia

What Are The Symptoms Of Scale Insects?

Symptoms of scale insects can vary from insect to insect, but common symptoms include:

  • Reduced plant vigor
  • The presence of scale, which can be “armored” or “soft”
  • Leaf yellowing and dropping
  • Twig and limb death in severe cases

What Are The Treatments For Scale Insects?

Scale can be treated and controlled through correct tree health care, like proper watering, mulching, pruning, and air movement. In severe cases, an ISA-certified arborist can apply a horticultural spray to control the scale population.

Before treating your trees for suspected scale, hire an ISA-certified arborist to inspect your trees to determine the problem and recommend the correct treatment.

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