WSU Extension

Hortsense

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


Biology
Hawthorn aphids are yellow-green to pinkish, soft-bodied insects typically found on the leaves in the spring. Aphid feeding causes young leaves to curl tightly and turn purplish. Older leaves are crinkled and deformed. Feeding aphids produce large amounts of honeydew, a sweet, sticky material that may attract ants or become covered with a dark growth of sooty mold.
Management Options

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

Chemical Management


Thorough coverage of the foliage is important, including lower leaf surfaces. Apply when aphids begin to increase in numbers. 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
  • 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