In an effort to protect wildlife habitat, the Pennsylvania Game Commission plans to spray over 123,000 acres of state game lands this spring to control a non-native invasive insect, the spongy moth.

Spraying is planned on 46 different state game lands – 123,276 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 only temporary, 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.”

No spraying will be scheduled the mornings of youth turkey season – Saturday, April 27 – or the opening day of spring gobbler season – Saturday, May 4.

Spongy moths previously were known by the common name gypsy moth, but the Entomological Society of America changed the name. 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 www.pgc.pa.gov.

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.

“Many of these areas were hit with a late frost last spring, Weiss said. “This additional stress on the trees makes it especially important to protect them this year.”  

This year’s spraying will occur in the following regions: Southcentral, Northcentral, Southeast, Southwest, and Northeast. The Northwest Region has no spraying scheduled this year. 

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 is aggressively treating this problem to protect the wildlife resources, in the immediate future and long term.

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. Over-winter survival and reproduction for deer 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. So the actions we take now help to keep all of that in balance.”