Forest Insects

Southern Appalachian trees are hosts for a variety of insects. Although most insects are vital to maintaining ecosystem functions, several species have been introduced from Europe and Asia and, due to a lack of natural endemic controls, have threatened the survival of several southern tree populations. Factors such as fire supression, drought, and air pollution also influence periodical outbreaks of native insects causing tree mortality. The damage by insect pests impact forest by stressing and killing trees which can lead to increased fire risks, reduction in wildife habitat, loss of timber resources, endangerment of rare species, loss of biodiversity, and promotion of invasive plants from increases in disturbance and light availability to the understory environment. The encyclopedia highlights some of the major pests and potential threats to forest health in the southern Appalachians.

Conifer Insects
Southern Pine Beetle Dendroctonus frontalis	Native to the United States, this beetle is a major pests of pines (Pinus spp) in the southeastern United States. It constructs galleries in the inner bark of trees, girdling and killing the tree.
Hemlock Woolly Adelgid Adelges tsugae	An exotic insect that has seriously threatened the health and sustainability of hemlocks in the eastern United States. They feed upon the nutrients of the young twigs by piercing the bark near the base of needles.
Balsam Woolly AdelgidAdelges piceae	Introduced around 1900 from Europe, this insect is well established in the southern Appalachians where it is the major pest of Fraser fir (Abies fraseri). Feeding causes the Fraser fir to produce abnormal wood cells, leading to difficultly in translocating water and nutrients.
Hardwood Insects
Gypsy MothLymantria dispar	This moth is an exotic insect introduced from Europe in the mid 1800s. It is a major pest of hardwoods (especially oaks, Quercus spp.) in the northeast. It is currently expanding its range south through the Appalachians. The caterpillars of this species feed upon the leaves of trees, defoliating, stressing, and eventually killing them.
Red Oak BorerEnaphalodes rufulus	This native longhorned beetle is a major pest of red oaks throughout the eastern United States. The larva bore into the wood, damaging but rarely killing trees. Damage caused by this insect causes defects in and degrades lumber, resulting in millions of dollars worth of losses.
Asian Longhorned BeetleAnoplophora glabripennis	This species was introduced into the United States sometime around 1990. It has been found in many nurseries but, as yet, escaped populations have been found only in New York, Illinois, and New Jersey. This insect bores into and feeds upon a variety of hardwood trees, including maples, elms, birches, willows, and poplars. The potential threat to the southern Appalachians is uncertain.
Emerald Ash BorerAgrilus planipennis	This insect is a newly introduced species (found in 2002) from Asia and populations have been found in southern Michigan, Ohio, and Indiana. Maryland has also reported an infested tree nursery. Larvae feed on the phloem and sapwood of ash species (Fraxinus spp.) girdling and killing the trees. Ash trees throughout the southern Appalachians are potentially at risk.