WSU Extension


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

print version| pdf version| email url    
Caption: Aphid colony
Photo by: A.L. Antonelli
Filbert : Filbert aphid
(revision date: 3/22/2021)

Filbert aphids are small, yellowish-green, pear-shaped insects typically found on the leaves. Aphids are often found in colonies on the tender new growth. Heavy aphid feeding may result in stunting and distortion of leaves and shoots. Severe infestations may cause foliage to show signs of water stress. Filbert aphids produce honeydew, a sweet, sticky material which may attract honeydew-feeding ants or become covered with a growth of dark sooty mold.
Management Options

Non-Chemical Management
  • Encourage natural predators including ladybird beetles, lacewings, syrphid (hover) fly larvae, and parasitic wasps. Avoid use of broad-spectrum insecticides which kill these beneficial insects.
  • Hand-wipe or prune to control small, localized infestations when practical.
  • Wash aphids from tree with a strong stream of water.
  • Control honeydew-feeding ants, which may protect aphid colonies from predators.
  • Provide proper nutrition. High levels of nitrogen encourage aphid reproduction. Switch to a slow-release or low-nitrogen fertilizer.
Select non-chemical management options as your first choice!

Chemical Management

Esfenvalerate is toxic to bees. Do not apply products containing esfenvalerate on or near blooming plants. To minimize risk to bees, apply in the evening after bees have stopped foraging for the day. 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.
  • Bug Buster-O [Organic]
    Active ingredient: pyrethrins  |  EPA reg no: 1021-1771-54705
  • Monterey Bug Buster II
    Active ingredient: esfenvalerate  |  EPA reg no: 1021-1778-54705
  • Safer Brand Insect Killing Soap with Seaweed Extract II [Organic]
    Active ingredient: potassium salts of fatty acid  |  EPA reg no: 42697-59
  • This list may not include all products registered for this use.

+ Show larger images

Caption: Aphid colony
Photo by: A.L. Antonelli
Caption: Aphid cast skins
Photo by: R.S. Byther