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U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Invasive Pest Risk Maps

European Gypsy Moth - Lymantria dispar dispar

The European gypsy moth (EGM), Lymantria dispar dispar, is one of North Americas' most destructive invasive forest pests. It was accidentally introduced into the United States near Boston, MA in the late 1890s. Since its introduction, EGM has expanded its range to encompass the mid-Atlantic and Northeastern States, as well as Counties in Ohio, Michigan, Indiana, Illinois, and Wisconsin. Because EGM introductions have been detected in western states including CA, OR, UT, and WA, considerable efforts are made each year at the state and federal levels to detect new infestations, eradicate isolated populations, and limit the spread of EGM beyond the known infested area.

The EGM risk assessment provides an objective, science based approach to quantifying the risk of EGM introduction, establishment, and susceptibility. The goal of the project is to: 1) improve the effectiveness of the EGM survey, 2) increase timeliness of detections outside the known infested area, and 3) identify places that require further monitoring. The following EGM risk assessment products were developed by the USDA Forest Service, Forest Health Assessment and Applied Sciences Team in co-operation with the Animal and Plant Health Inspection Service, Plant Protection and Quarantine, and the U.S. Geological Survey staff members, to address the needs of EGM Program Managers at both the State and Federal levels.

Risk Maps (Contiguous US)
Map Type Map Methods
Short Range Introduction Adobe Acrobat File 502KB Adobe Acrobat File 605KB
Long Range Introduction Adobe Acrobat File 772KB Adobe Acrobat File 871KB
Combined Introduction Adobe Acrobat File 812KB Adobe Acrobat File 910KB
Establishment Suitability Adobe Acrobat File 902KB Adobe Acrobat File 932KB
Detection Likelihood Adobe Acrobat File 862KB Adobe Acrobat File 885KB
Survey Sample Area Adobe Acrobat File 635KB Adobe Acrobat File 655KB
European Gypsy Moth Information:

USFS Gypsy Moth Information (Website)

USDA Gypsy Moth Information (Website)

USDA Gypsy Moth Program Manual (PDF)

Slow the Spread (STS) of the Gypsy Moth (Website)