True Fir: Giant conifer aphids
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
See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.
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: Always read and follow label directions when working with pesticides.
For more information on using pesticides visit :
- 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
If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.
Additional Image
Photo by: A.L. Antonelli
WSU Extension programs and employment are available to all without discrimination.
Evidence of noncompliance may be reported through your local Extension office.