Pine bark adelgid (Pineus strobi)

U.S. Department of Agriculture, Forest Service. 1979. A guide to common insects and diseases of forest trees in the northeastern United States. Northeast. Area State and Private Forestry, Forest Insect and Disease Management., Broomall, PA. p. 123, illus.(USDA Forest Service, Northeast Area State and Private Forestry Publication. NA-FR-4)

The pine bark adelgid prefers eastern white pine, but also attacks Scots and Austrian pines. Although mature white pine trees may become unsightly when heavily infested, they seldom are damaged. However, ornamentals in park and recreation areas and also nursery stock may be injured seriously. Needles turn yellow in younger trees, and feeding damage may cause stunting or death. In older trees, large patches of white cottony material may cover the tree trunk and branches giving a whitewashed appearance.

In the spring, females lay eggs that produce both winged and wingless females. Wingless forms remain on the host tree and reproduce several times. Some of the winged forms may fly to spruce instead of white pine, where they settle on the needles, lay eggs, and die. The larvae cannot survive on spruce, however. Up to five generations have been recorded as far north as the Lake States.