Forest Service to employ aerial spraying against spongy moths

Release Date: 

Contact: District Ranger Mary Yonce


Forest Service to employ aerial spraying against spongy moths 

Edinburg, Va. May 6, 2024 — The George Washington – Jefferson National Forest in partnership with the Shenandoah National Park begin aerial suppression treatments of nonnative spongy moth caterpillars across sections of the Lee and North River Ranger Districts on Monday. Treatments will continue periodically until May 18, 2024, depending on weather conditions.

The U.S. Department of Agriculture, Forest Service will use a naturally occurring bacteria - Bacillus thuringiensis var. Kurstaki, or Btk, as an aerial pesticide. Btk is widespread in natural ecosystems and is not harmful to humans, pets, plants, or most beneficial insects. The spray will not cause harm to painted surfaces and can be removed with soap and water. Btk is registered with the U.S. Environmental Protection Agency and is sanctioned by the U.S. Department of Agriculture for use against spongy moths. 16,000 acres total will be sprayed from a specialized helicopter in May planned to help minimize spongy moth spread onto adjacent lands. 

Over the past two years, spongy moth numbers have grown causing forest defoliation in large areas in the northern Shenandoah Valley. Additional defoliation would likely cause significant tree mortality, which would create safety hazards in high visitor-use areas and damage forest habitats. “With the help of the National Park Service and the Virginia Department of Forestry, the aerial treatments on the George Washington – Jefferson National Forest will meet the goals of the National Forests Spongy Moth Suppression Program to protect visitor health and safety, reduce hazard tree development, and to protect sensitive historic and natural areas,” said District Ranger Mary Yonce. 

These suppression goals will not eliminate spongy moths from the George Washington – Jefferson National Forest completely but will minimize their impacts in targeted infestation areas. Treatment areas were chosen based on USFS egg mass population surveys during the fall of 2023 and aerial defoliation mapping conducted by the Virginia Department of Forestry in June 2023.  

For more information, please contact the North River Ranger District at 540-432-0187, visit our website at or follow us on Facebook and Twitter.  


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