Cinara curvipes
See:
Pest description and crop damage About 200 species of Cinara attack pine, spruce, fir and cypress throughout the United States. Many of these are large (up to 0.2 inch), dark brown to black, and almost spider-like. Aphids congregate in large colonies to feed on the bark of twigs and even the main stem of small trees. The feeding causes yellowing of foliage, leaf drop and can cause limbs to die. Serious damage can be done to young trees.
Biology and life history These aphids overwinter as eggs on twigs or branches. Adults and nymphs begin feeding on stems in the spring.
Management-biological control
See:
Biological Control of Nursery Pests
Management-cultural control
Hand-wipe to remove minor infestations when possible. Hose infested trees with a strong stream of water to wash off these insects.
Management-chemical control
See:
Chemical Control of Nursery Pests
It is important to cover foliage thoroughly, including lower leaf surfaces.
See "True fir" in:
Christmas Tree Plantation Pests
For more information
Johnson, W.T. and H.H. Lyon (1991), Insects That Feed on Trees and Shrubs, 2nd ed., Cornell University Press (p. 82-84).