Pennsylvania Game Commission Announces Spraying Plans

In an effort to protect wildlife habitat, the Pennsylvania Game Commission plans to spray nearly 110,000 acres of state game lands this spring.

Spraying will occur on 43 different state game lands – 109,180 acres in all – and will begin as soon as leaf-out occurs and spongy moth egg masses hatch, likely in late April and May.

“Those participating in spring gobbler seasons or otherwise enjoying state game lands may encounter aircraft spraying forested areas for spongy moths,” said Paul Weiss, Game Commission Chief Forester. “We recognize some hunters might be temporarily affected by these activities, but disturbances are brief, and by protecting these valuable habitats against a destructive, invasive pest, the forests will provide hunters the opportunity to chase gobblers there for generations to come.”

Spongy moths previously were known by the common name gypsy moth, but the Entomological Society of America changed the name last year. More information on spongy moths and the Game Commission’s spraying program, including a map updating the status of spraying is available on an interactive web page at

Most of the blocks of forest to be sprayed can be treated within one day, often within only a few hours.

The insecticide to be used is Mimic 2LV. Its active ingredient is tebufenozide.

This agent generally is considered safe to humans. Most negative side effects happen with repeated, long-term exposure to high concentrations of the product. As with any chemical, it may cause eye or skin irritation if exposed, and it is recommended to wash any affected area if irritation occurs.

The forests to be treated in the coming weeks have building populations of spongy moths that, if left untreated, could cause severe defoliation this summer.

This year’s spraying will occur in the following regions: Southcentral, 1,323 acres; Northcentral, 94,788 acres, Southeast, 3,107 acres, Southwest, 226 acres and Northeast, 9,736 acres. The Northwest Region had spraying last year, but the spongy moth population there seems to be in decline and, as such, no spraying is scheduled in that region.

Weiss noted that previous spongy moth impacts unfortunately led forests on state game lands to transition from mast-producing mixed-oak stands to stands dominated by birch and maple, which are not nearly as beneficial to wildlife.

“Oaks are the main target of spongy moths, and they also provide the best and most reliable wildlife foods,” Weiss said.  “Unfortunately, in some areas, we have seen birch and maple replace the oak stands lost to past spongy moth defoliation. This loss of acorn availability across such a potentially large area can have extremely detrimental impacts on wildlife populations ranging from chipmunks and squirrels all the way up to deer and bears. Even if the oak trees manage to survive damage caused by this defoliation, the reduction of acorn production can linger for years after. The Game Commission has made the decision to aggressively treat this problem to protect the wildlife resources in the immediate future as well as into the longer term.”

After partnering with the state Department of Conservation and Natural Resources to have game lands treated several times since 2008, the Pennsylvania Game Commission carried out its first independent spray contract in 2022. That program was, at the time, the largest-ever spray effort on game lands at approximately 63,000 acres. Similar to 2023, the bulk of those acres were in the Northcentral Region.

“We believe it is very important to continue protecting the habitats in these areas,” Weiss said.

David Gustafson, director of the Game Commission’s Bureau of Wildlife Habitat Management, noted that, based on the value of state game lands’ oaks for wildlife, the agency simply can’t afford to forgo spraying this year.

“We know that oak forest habitats are tremendously valuable to all wildlife,” Gustafson said. “Everything from squirrels to bears to turkeys will have populations fluctuate based on acorn crops. If acorn production is low, bears will den earlier, weigh less, produce fewer and smaller cubs and get into more nuisance situations. Deer over-winter survival and reproduction suffers when acorns are sparse. Neo-tropical birds, such as cerulean warblers, occupy habitats dominated by oaks.  Wild turkey and ruffed grouse populations also depend on acorns.”