Biologists and foresters at the Park use Integrated Pest Management (IPM) to control exotic and invasive pests. There are three types of IPM: mechanical (such as hand-pulling weeds), cultural (such as changing behavior to prevent or reduce pests), and chemical (using approved pesticides or herbicides). Managers deal with pests in forests, fields, and even park buildings, trying to protect native species and people.
Here are examples of five forest insect pests and diseases in the Great Smoky Mountains that managers actively monitor:
Balsam Woolly Adelgid (BWA) - An aphid-like insect, BWA killed 90 percent of mature fir trees in the park since 1962 when it was first found in the park. The Fraser fir, a federally listed species of concern and a southern Appalachian endemic (meaning it’s found only in these mountains, and most of them are found within the boundaries of the Park), has been hit hard. Managers spray fir trunks with insecticidal soap, although there is no completely effective treatment. Fir stands that survived have begun to reproduce in many areas.
Beech Disease - Beech stands have been devastated in many areas of the Park by a combination of non-native beech scale and a species of Nectria fungus first identified in the late 1980s. Look for loss in high elevation beech gaps along the Appalachian Trail.
Butternut Canker - The butternut canker causes lens shaped bark wounds and lesions on butternut tree nuts and branches. The disease first appeared in Wisconsin in 1967, although no one knows where it originated. Scientists began monitoring 75 butternut trees in 1987.
Dogwood Anthracnose - Many flowering dogwoods in the Park—and in the United States—are afflicted with this fungus. Its origins are unknown, and there are no effective treatments. Vegetation managers monitor surviving dogwood.
Hemlock Woolly Adelgid (HWA)—Since 1992, hemlock woolly adelgid or HWA, has infested eastern hemlocks throughout the Park. HWA is an aphid-like insect that feeds at the base of hemlock needles, killing trees directly or weakening them so secondary pests such as hemlock borer eventually kill the trees. Foresters treat the trees with systemic chemical control (pouring insecticide around the tree base), foliar spray of insecticidal soap or oil, and/or biological control (using predatory beetles). Most untreated hemlocks are dying.
Pests and disease come to the park in many different ways. Once in the United States, the Hemlock Woolly Adelgid spread by itself from forest to forest over many years, while the Emerald Ash Borer, another insect pest, arrives on firewood that campers bring into the park from infested areas. Read more about the Firewood Quarantine to see how you can help stop the spread of this invasive and destructive insect.
Return to Meet the Managers: Issue 1.