WSU Extension


Caption: Eastern filbert blight
Photo by: R.S. Byther
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Filbert : Eastern filbert blight
(revision date: 2/14/2019)

Eastern filbert blight is a fungal disease found on both cultivated and wild filberts. The disease typically infects via wounds caused by mechanical or insect damage. Buds damaged by the filbert bud mite may be particularly susceptible. Buds, twigs, and stems may be infected. The disease causes cankers, sometimes girdling and killing branches in summer to early fall. Cankers are typically somewhat sunken and may be surrounded by a ridge of callus tissue. The wood beneath the canker is stained dark brown. The bark of infected twigs may develop rows of bumps or pustules which split open to reveal white fungal fruiting bodies. The sticky white spores are released during wet weather through winter and early spring. The ornamental contorted hazelnut (Corylus avellana 'Contorta') may also be infected.
Management Options

Non-Chemical Management
  • Plant moderately resistant varieties such as 'Hall's Giant', 'Tonda di Giffoni', or 'Willamette'.
  • Some varieties used as pollenizers are susceptible to infection, including 'Butler' and 'Daviana'. The cultivars 'Ennis' and 'Tonda Romana' are also susceptible.
  • Prune out and destroy cankered branches. Make pruning cuts at least 3' below canker.
  • Remove severely infected trees.
  • Avoid overhead watering during the period spanning bud break through shoot elongation. Spores are spread by rain and splashing water.
Select non-chemical management options as your first choice!

Chemical Management

For timing of chemical applications, consult local references such as the online PNW Plant Disease Management Handbook ( Thorough coverage of all branches is essential. 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.
  • Hi-Yield Vegetable, Flower, Fruit & Ornamental Fungicide
    Active ingredient: chlorothalonil  |  EPA reg no: 60063-16-7401
  • Monterey Liqui-Cop Copper Fungicidal Garden Spray
    Active ingredient: copper-ammonia complex  |  EPA reg no: 54705-7
  • This list may not include all products registered for this use.
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Caption: Eastern filbert blight
Photo by: R.S. Byther
Caption: Eastern filbert blight
Photo by: R.S. Byther
Caption: Dieback from eastern filbert blight
Photo by: R.S. Byther