NC State Extension Publications

Description and Biology

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Giant conifer aphids, genus Cinara, are soft-bodied insects that are often found in large groups on conifers in the landscape. Giant conifer aphids are large (up to 1/4 inch long), long legged, and dark. Most aphids have a pair of tube-like structures on the abdomen called cornicles. The cornicles of Cinara aphids are cone-shaped. These aphids are wingless or may have wings. They have slender mouthparts that are used to suck sap from twigs, branches, trunks, and roots. Most species are restricted to feeding on one genus of tree. Some Cinara aphids such as the white pine aphid attack only one tree species. We have several generations a year in North Carolina. In spring, tiny aphids hatch from overwintering eggs. They molt through several stages, becoming larger with each molt. During the growing season all giant conifer aphids are females that give birth to live young. The last summer generation develops into males as well as females. They mate, and females lay eggs on needles or bark. Aphids secrete honeydew as they feed, and other insects, especially ants, bees, and wasps, feed on the honeydew. Some species of ants protect aphids from predators in order to harvest the honeydew.

Cinara aphid feeding on a juniper stem.

Cinara aphids on juniper.

Photo by J.R. Baker

Cinara aphids being tended by ants on a pine sapling.

Cinara aphids on loblolly pine sapling.

Photo by J.R. Baker

Cinara aphid feeding on Scots pine.

Cinara aphid feeding on Scots pine.

Photo by J.R. Baker, NC State University

Host Plants

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Each Cinara species is specific to a tree genus or even a tree species. Heavy infestations of giant conifer aphids cause yellowing of the foliage and reduce tree growth, especially in young trees. Young seedlings may be killed by these aphids. Populations are usually highest in late spring and may crash by early summer. The best evidence of an aphid population is the presence of honeydew (clear, sugary, sticky liquid), ants attracted to honeydew, or ladybeetles and hover flies that prey on aphids. Honeydew is also a good growth medium for sooty mold and infested host conifers often become dark, sometimes almost black. Sooty molds also grow on the ground cover under a heavily infested tree.

Residential Recommendation

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Several lady beetles, lacewings, and hover flies specialize in feeding on aphids. Parasitic wasps also prey on aphids. If it becomes necessary to treat, a dozen or so insecticides, including horticultural oils and insecticidal soaps, are registered for aphid control. When using any pesticide, thorough coverage is necessary. However, avoid spraying white pines and spruces with oils. Oils can remove the waxy bloom that give these trees the bluish appearance and treated trees may have a sickly yellow-green color until the wax is replaced or new foliage appears to mask the yellowish foliage. On such trees, consider using a systemic pesticide such as imidacloprid for aphid suppression.


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For assistance with a specific problem, contact your local N.C. Cooperative Extension Center.

This Factsheet has not been peer reviewed.


Professor Emeritus
Entomology and Plant Pathology

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Publication date: Nov. 12, 2013
Revised: Oct. 31, 2023

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