PENNSYLVANIA (WHTM) — The Department of Conservation and Natural Resources (DCNR) Secretary Cindy Adams Dunn announced the start of aerial spraying of state forests to combat the spongy month, which was formerly known as the gypsy moth.

“Suppression efforts are commencing now as these insects emerge and begin feeding,” Dunn said. “As the statewide leader in protecting our Commonwealth’s natural resources, we are conducting aerial spraying to keep this invasive pest in check and protect the trees from defoliation to maintain Pennsylvania’s 2.2 million acres of state forests.”

According to the DCNR, in 2022, the spongy month defoliated over 850,000 acres in Pennsylvania alone.

The DCNR will oversee the spraying of 274 sites, with a total of 290,753 acres. These spraying efforts will cost more than $6 million, using a combination of general funds, DCNR Special Funds, and federal funds.  

“In Pennsylvania, these destructive, invasive insects go through cycles where outbreaks generally occur every five to 10 years,” DCNR Forest Health Manager Rosa Yoo said. “Populations had declined in 2019 and 2020 thanks to the spongy moth fungus disease and wet spring weather, but that no longer is the case in 2021 and 2022, resulting in the need for suppression efforts.”

DCNR Bureau of Forestry experts states that the state’s oak is especially vulnerable to infestations, which result in tree mortality. A tree begins to really suffer when 30% or more of its leaf surface is lost.

The moth was introduced to North America in 1869 at Medford, Massachusetts where it was used in a failed silk-production experiment. The spongy moth first reached Pennsylvania in Luzerne County in 1932, and since then has infested every county, according to the DCNR.