Arborvitae: Juniper scale

categories: Arborvitae Arborvitae Insects Conifers Ornamentals

revision date: 2024-06-05 02:05

Green arborvitae leaves with white spots that are the scale.
Juniper scale
Photo by: Unknown


Juniper scale is a small, round, white to gray scale with a yellow dot at the center. Leaves, twigs and branches may be attacked. Symptoms of scale feeding include loss of normal color and luster of foliage, lack of new growth, and yellowing and death of branches. Severe infestations are rare, but may kill plants. The scales excrete large amounts of honeydew, a sweet, sticky material. Honeydew may attract ants, or may become covered with a growth of dark sooty mold. Red cedars and Pfitzer, Irish, and Savin junipers are also commonly attacked.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • Ladybird beetles and parasitic wasps help control scale infestations.
  • Minor infestations may be wiped off by hand, when practical.
  • Prune and destroy heavily infested branches to help control localized infestations.
  • Provide proper culture. Healthy plants are more able to tolerate damage.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • Make applications to control the immature crawlers in late spring to early summer.
  • Do not apply soap products to plants stressed by drought or when tender new foliage is present.
  • Do not apply soap in full sun or when temperatures exceed 90° F.
  • When using Safer Brand Insect Killing Soap Conc II, test a small area for sensitivity before application.
  • Homeowners should not make foliar applications to trees over 10 ft tall.
  • Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.