WSU Extension

Hortsense

Common Insects & Mites : Conifer aphids
(revision date: 4/30/2013)


Biology
Conifer aphids are often large black aphids that attack only coniferous trees. There are a few species that are smaller, green, and develop powdery white waxy material over their bodies. The large black ones frequently feed on growth tips (leaders) and twigs. As their numbers increase, they produce a sticky liquid secretion called honeydew. This can "rain" on cars, sidewalks, and lawn furniture causing a serious nuisance problem. Honeydew is also a problem in that it serves as a food for the black sooty mold fungus, as well as attracting honeydew-feeding insects such as ants. Conifer aphids that feed on needles often cause curling or twisting of the needles due to toxins in their saliva. Honeydew problems are also associated with these aphids.
Management Options

Non-Chemical Management
  • Hose aphids off smaller trees with a strong stream of water.
  • Encourage natural enemies of aphids.
  • Purchase and release lacewings and parasitic aphid wasps.
Select non-chemical management options as your first choice!

Chemical Management

Pesticide applications are generally not recommended. If you choose to make an application, make certain that the pesticide applied is registered for the host and effective against the pest. 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.

Images
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Caption: Giant conifer aphids on pine
Photo by: A.L. Antonelli
Caption: Giant conifer aphids
Photo by: A.L. Antonelli