The Pennsylvania Department of Conservation and Natural Resources (DCNR) has launched an aerial spraying initiative across various state woodlands to suppress burgeoning populations of the spongy moth (Lymantria dispar dispar), previously known as the gypsy moth. According to DCNR Secretary Cindy Adams Dunn, the effort aims to mitigate the anticipated spring outbreaks that threaten extensive defoliation of native forests, particularly oak trees.
This invasive species’ larval stages feast on foliage, leading to stressed trees susceptible to disease, other pests, or drought. With oaks being a crucial habitat and resource, maintaining forest health is essential for recreational, environmental, and economic benefits.
The operation encompasses 185 designated spray sites totaling 227,820 acres, including parts of 12 state forests and 18 state parks and the Grey Towers National Historic Site. Two helicopters and six fixed-wing aircraft will execute the spraying, which targets high-risk areas identified through egg mass surveys and other indicators.
In 2023, spongy moths devoured leaf cover across 441,819 acres in the state, a decrease from the previous year’s 850,000 acres. This signaled a potential downturn in the pest’s activity but underscored the ongoing need for control measures. The treatment employs environmentally approved insecticides like tebufenozide and Bacillus thuringiensis subsp. kurstaki, which caterpillars must ingest during early feeding stages.
The DCNR’s campaign, supported by the USDA Forest Service’s Forest Health Protection Unit and paralleled by the Pennsylvania Game Commission’s efforts on State Game Lands, reflects a continued commitment to preserving Pennsylvania’s vital forest ecosystems against this cyclic pest threat. Residents can track progress via the DCNR Spongy Moth Daily Spraying Status GIS Map available on their website.