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USDA Forest Service

NCRS - The Changing Midwest Assessment

Gypsy Moth

The gypsy moth is one of the most destructive forest pests in the Eastern and North Central United States. It was introduced in 1869 and has been detected and/or established in all 7 of the states in the North Central Region, and continues to spread at a rate of 13 miles per year in areas without a comprehensive intervention strategy. Larvae prefer hardwoods, but may feed on hundreds of species of trees and shrubs, including pines, cedars, hemlocks, and spruce. The moth prefers oaks, apple, sweetgum, speckled alder, basswood, gray and white birch, poplar, willow, and hawthorne, although other species are known to be affected, and the list of suitable hosts will undoubtedly expand as the insect spreads. The effects of defoliation range from reduced growth and die back of twigs and branches, to mortality, depending on tree vigor, as well as the severity and frequency of defoliation events. Hardwood species are more resilient than softwoods; pines and hemlocks subject to heavy defoliation are likely to die after a single defoliation event of greater than 50 percent.

To learn more, see Forest Service Forest Insect and Disease Leaflet 162. To view maps and animations depicting changes in the presence and establishment of the gypsy moth, choose either Flash format or continuous animation.

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USDA Forest Service - North Central Research Station

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