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True Fir: Giant conifer aphids

categories: Conifers Ornamentals True Fir True Fir Insects

revision date: 2023-04-04 12:00

Colony of black Giant conifer aphids on branch.
Giant conifer aphids on pine
Photo by: A.L. Antonelli

Biology

Giant conifer aphids are large (up to 1⁄5″) and dark brown to black in color. They overwinter as eggs on twigs or branches. Adults and nymphs begin feeding on stems in the spring. They excrete large amounts of honeydew (a sweet, sticky material), which may become covered with sooty mold, a black fungus.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • Provide proper plant culture. Healthy plants can tolerate more insect damage.
  • Avoid overfertilization. High levels of nitrogen in the foliage encourages aphid reproduction. Switch to a slow-release or low-nitrogen formula if necessary.
  • Hose infested trees with a strong stream of water to wash off insects.
  • Where practical, prune and destroy individual, heavily-infested branches.
  • Encourage natural aphid predators, including ladybird beetles and green lacewings.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • Thorough coverage of the foliage is important, including all needle surfaces.
  • Apply one of the following in the spring.
  • 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.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

  • Ortho Max Malathion Insect Spray Concentrate
    Active ingredient: malathion [EPA registration number: 239-739]
  • R-T-U Year-Round Spray Oil
    Active ingredient: oil/pet distillate [EPA registration number: 6218-78]
  • Safer Brand BioNEEM Multi-Purpose Insecticide and Repellent Concentrate [Organic]
    Active ingredient: azadirachtin [EPA registration number: 70051-6-42697]
  • Safer Brand Insect Killing Soap Concentrate II [Organic]
    Active ingredient: potassium salts of fatty acid [EPA registration number: 42697-60]
  • This list may not include all products registered for this use.

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