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U.S. Forest Service
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United States Department of Agriculture

Forest Health News 2020

20 Years of Slow the Spread of the exotic Lymantria dispar dispar

By Tom Coleman, USDA Forest Service


September 2020

20 Years of Slow the Spread activity

Slow the Spread activity. Photo by: Tom Coleman.

The National Gypsy Moth Slow the Spread Program (STS) has actively suppressed Lymantria dispar dispar dispar, populations for 20 years. The STS program was formalized in 2000 but incorporates aspects of several previous Lymantria dispar integrated pest management programs that date back to the 1920s. The program has successfully suppressed Lymantria dispar populations on >9.5 million acres, including its pilot years (1993-1999), along the leading edge of infestations from North Carolina to Minnesota. Most of these treatments represent aerially applied mating disruption and biological control techniques. The program continues to reduce the rate of spread of Lymantria dispar dispar by >60% and limiting its advancement into Midwestern and Southeastern states.

Aerial application being conducted for STS

Aerial application being applied to slow the spread of Lymantria dispar dispar. Photo by: Tom Coleman.

For more information about Lymantria dispar in the U.S., its management, and the STS program, visit the Natioinal Gypsy Moth Slow the Spread Program story map.