Spongy Moth Suppression Treatment to Occur Allegheny National Forest will use Aerial Spraying to Combat Invasive Insect

Release Date: May 18, 2022

Contact(s): Christopher Leeser, Public Affairs Officer

Warren, PA, May 16, 2022 - The US Department of Agriculture, Forest Service plans to suppress spongy moth populations by aerially applying a naturally occurring native bacterium, Bacillus thuringiensis subspecies kurstaki (B.t.k), to the crowns of overstory trees. The Allegheny National Forest is partnering with the Pennsylvania Department of Conservation and Natural Resources (PA DCNR) for this suppression activity. PA DCNR will be leading the operations with a PA DCNR contractor applying the (B.t.k) using a helicopter. Treatment will occur during the last two weeks of May and into early June on 11,874 acres of Allegheny National Forest. You may notice additional trees being treated throughout the region by state and private landowners. Specific dates of operation over the national forest cannot be determined because operations are weather-dependent and to achieve maximum results are based on the stages of caterpillar development. Our best estimate is that treatments could begin as early as Saturday, May 21.

Updated information on daily treatments will be available on Allegheny National Forest social media and the PA DCNR interactive map. Most treatments will occur in little-visited, heavily forested areas. Some public recreation areas including, Jakes Rocks Mountain Bike Trail, Morrison Hiking Trail, Tracy Ridge Hiking Trail, and Tracy Ridge Campground will also be treated. Signboards will be posted at trailheads and recreation sites on the day of aerial operations and Forest Service staff will be present to answer questions during suppression activity. A portion of the Kinzua Beach parking area may serve as a helicopter landing zone, but the day-use area will remain open to the public.

Treatments are focused on oak forest types that were heavily defoliated in 2021 and where high spongy moth egg mass counts have been recorded, which indicates a high likelihood of defoliation this year. Two consecutive defoliations on oak trees may result in tree death and decline. This year noticeable defoliation is expected in the Allegheny National Forest where treatments are not occurring.

B.t.k is a naturally occurring native bacterium and is not considered toxic to humans, wildlife, fish, or other biota. B.t.k is used in organic farming and conventional farming to control leaf-feeding caterpillars on vegetables, fruits, and other crops. Spongy moth caterpillars that eat enough B.t.k die after a few days.

In July of 2021, the Entomological Society of America adopted spongy moth as the new common name for the species Lymantria dispar, referring to the insect's distinctive sponge-like egg masses. The name replaces gypsy moth due to the word gypsy being a widely acknowledged ethnic slur and the subsequent dehumanizing effects when used as a common name.