WSU Extension

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Caption: Aphid colony
Photo by: Unknown
  
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Maple : Aphids
(revision date: 4/11/2018)


Biology
Various species of aphids can occur on maples. They are typically small, yellowish-green insects that feed on the leaves and produce large amounts of honeydew, a sweet, sticky material. The honeydew may attract ants which feed on it, or it may become covered with a growth of black sooty mold. Aphid feeding may cause minor to severe leaf loss (especially on silver and Norway maples). Leaves that are damaged during growth may be curled or distorted.
Management Options

Non-Chemical Management
  • Hand-wipe or prune to control small, isolated infestations when practical.
  • Wash aphids from foliage with a strong stream of water.
  • Encourage natural enemies, including ladybird beetles, lacewings, and parasitic wasps. Natural enemies help keep aphid populations in check.
  • Control honeydew-feeding ants, which may protect aphid colonies.
  • 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 aphid buildup is noticed. Do not apply acephate products to sugar maple or red maple as foliage injury may occur. Since many species of aphids overwinter as eggs on their host, a delayed dormant oil application might be considered. Safer Brand Insect Killing Soap Concentrate II is NOT registered for use on Japanese maple! 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.
  • 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: Aphid colony
Photo by: Unknown
Caption: Aphid cast skins
Photo by: R.S. Byther