WSU Extension

Hortsense

Filbert
 
Disease
Bacterial blight 
Eastern filbert blight 
Powdery mildew 
Insect
Apple mealybug 
Brown marmorated stink bug 
Filbert aphid 
Filbert bud mite 
Filbert leafroller 
Filbertworm 
Lecanium scale 
Omnivorous leaftier 
Tent caterpillars 



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Caption: Lecanium scales
Photo by: R.S. Byther
  
Filbert : Lecanium scale
(revision date: 3/10/2017)


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


Non-Chemical Management
  • 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.
Select non-chemical management options as your first choice!

Chemical Management

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.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Pyola Insect Spray
    Active ingredient: canola oil, pyrethrins  |  EPA reg no: 67702-5-56872
  • Safer Brand Insect Killing Soap with Seaweed Extract II [Organic]
    Active ingredient: potassium laurate  |  EPA reg no: 42697-59
  • Whitney Farms Outdoor Insect Killer
    Active ingredient: canola oil, pyrethrins  |  EPA reg no: 67702-6-73327
  • Worryfree Brand Garden Insect Killer RTU
    Active ingredient: canola oil, pyrethrins  |  EPA reg no: 67702-6-33116
  • This list may not include all products registered for this use.
Images

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Caption: Lecanium scales
Photo by: R.S. Byther