WSU Extension


Caption: Green peach aphid
Photo by: Unknown
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Ornamental Pear : Aphids
(revision date: 2/14/2019)

Three aphids are commonly found infesting pear. All three species produce honeydew, a sweet, sticky material which attracts ants and that may become covered with a growth of dark sooty mold. Honeydew also causes russeting of pear fruit. The green peach aphid is pale green in color, the melon or cotton aphid is yellowish to dark green, and the bean aphid is black. The green peach and melon aphids feed on succulent shoots throughout the tree, while the bean aphid is primarily found in clusters on shoot tips. Aphid feeding causes foliage and shoots to be stunted, curled and deformed.
Management Options

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

Chemical Management

Apply superior spray oils to manage overwintering aphid eggs. Use insecticidal soap or azadirachtin as needed during the summer. Soaps may require several applications. 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.
  • All Seasons Horticultural & Dormant Spray Oil Conc [Organic]
    Active ingredient: oil/pet distillate  |  EPA reg no: 4-80
  • Hi-Yield Dormant Spray
    Active ingredient: oil/pet distillate  |  EPA reg no: 7401-428
  • R-T-U Year-Round Spray Oil
    Active ingredient: oil/pet distillate  |  EPA reg no: 6218-78
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • Safer Brand Insect Killing Soap Conc II [Organic]
    Active ingredient: potassium laurate  |  EPA reg no: 42697-60
  • This list may not include all products registered for this use.
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Caption: Green peach aphid
Photo by: Unknown
Caption: Aphid colony
Photo by: Unknown
Caption: Aphid cast skins
Photo by: R.S. Byther