General Impact
Adelges piceae feeds on all true firs with long, tube-like mouthparts, and they also secrete an irritating, salivary substance that elicits a defensive response from trees where the adelgid is not native. Balsam fir is the main host of A. piceae , where it attacks both stems and shoots . The principal injury associated with stem infestations seems to be obstruction of the water-conducting tissue. But some decline is probably related to obstruction in the phloem tissue, which has an important role in transporting and storing food. Stem attack results in the formation of dense compression wood, reducing the quality of the wood fiber that is used in pulp and paper manufacturing. Prolonged shoot attack will hinder bud growth and height growth. Tree vigor declines as photosynthetic function decreases and foliage is lost. No new needles replace those that are naturally shed. This ultimately leads to top kill and mortality of the whole tree. Infested Balsam and Fraser firs may be killed in only 3 to 4 years.
North American hosts are so sensitive to attack that the damage seems out of proportion to the insect's size and method of feeding. Billions of feet of fir timber have been destroyed by A. piceae in North America. It is a serious pest to seed production, landscape and natural fir, and fir Christmas tree industry. Attempts to control the insect have been unsuccessful, and the U. S. Fish and Wildlife Service listed the Fraser fir as a species of special concern. The massive decline of Fraser firs has placed plants and animals of the spruce-fir plant association in jeopardy. Twenty-seven species of mosses and liverworts frequently occur on the bark of Fraser firs, and eight of them occur exclusively on the bark of firs. A small tarantula and a lichen, which are federally listed endangered species, and two salamander species, are among the native species that occur only in spruce-fir forests.
Location Specific Impacts:North America 
Agricultural: Adelges piceae is a serious pest of seed production, landscape and natural Fraser fir and also causes considerable damage to the Fraser fir Christmas tree industry.
Economic/Livelihoods: Billions of feet of fir timber have been killed by Adelges piceae in North America. It affects seed production, landscape and natural Fraser fir and also causes considerable damage to the Fraser fir Christmas tree industry. Economic effects are felt in pulp and paper manufacturing because it degrades the quality of wood fiber.
Herbivory: The insects suck fluid from host trees with long, tube-like mouthparts. The fluid, called phloem, transports and stores the tree's elaborated food. This ultimately leads to mortality of the whole tree.
Modification of successional patterns: Some management techniques include clearing and burning infested trees, which resets the successional progression of the forest ecosystem.
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