Filbert: Lecanium scale

categories: Filbert Filbert Insects Tree Fruits

revision date: 2023-03-13 12:00

Yellow pencil pointing to Lecanium cales on twig shown on a black background.
Lecanium scales on twig
Photo by: R.S. Byther

Biology

Lecanium scales are shiny brown insects found on twigs. Adults are 1/8″-1/4″ in diameter and roughly turtle-shaped. They may have light markings or appear somewhat waxy. Crawlers (immature scales) are flatter. Scales produce large amounts of honeydew, a sweet, sticky material which may attract ants or become covered with a growth of dark sooty mold. Heavily infested branches may be wilted, yellowish, or show other signs of stress. New growth may be stunted or lacking. Twigs and small branches may be killed. Lecanium scale is a common pest in the landscape, infesting many plants including dogwood, maple, rhododendron, willow, and most fruit trees. Lecanium scales overwinter as immatures on the host.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

  • Natural enemies such as ladybird beetles, green lacewings, and parasitic wasps help control scale populations. Avoid use of broad-spectrum insecticides which kill these and other beneficial insects.
  • Control honeydew-feeding ants which may protect scales from predators.
  • Hand-wipe to help control minor infestations.
  • Prune and destroy heavily infested branches, when practical.

Chemical Management

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

  • 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.