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DCNR to resume spraying woodlands to combat gypsy moth damage
State woodland managers again are bracing for what could be a pitched suppression effort to combat remnants of a statewide gypsy moth population posed for spring outbreaks across the state, DCNR officials said early this month.

Heavy infestation was expected in some areas last spring but Bureau of Forestry entomologists said most of that gypsy moth population collapsed, thanks to a naturally recurring fungus. Last year, cold, wet weather proved ideal for the fungus, deadly to gypsy moths, but pest suppression efforts cannot always rely on the weather to be an ally, the entomologists said.

The bureau has stressed budgeted funds are necessary to maintain a continued year-to-year gypsy moth spraying program that suppresses rebounding insect populations while protecting the forest stands they may have damaged the spring before.

Surveys across the state indicate gypsy moth populations are increasing and have the potential to cause defoliation in 2015, especially in eastern Pennsylvania.

Funding must be consistently available to treat populations early in infestations when populations are of levels where success can be reasonably expected, bureau officials said. Guiding off staff recommendations, $2 million has been budgeted to enable DCNR to conduct a spray program on DCNR lands without dependency on federal funds. This consistent funding gives us the bureau the option to move forward with treatment if needed.

In 2014, gypsy moth populations increased in eastern Pennsylvania after several years of high populations in the northwestern part of the state. DCNR treated 1,901 acres in 42 spray blocks in May in four northwestern counties. Treatment areas were all private lands.

A 26,860-acre suppression program in 39 treatment blocks is proposed for 2015 in six northeastern counties—Carbon, Columbia, Luzerne, Northumberland, Pike and Schuylkill—principally on state-managed parks, forests, and game lands, but also some private residential lands in Carbon County.

Bureau of Forestry experts note the state’s oak stands are especially vulnerable to gypsy moth infestation and mortality. The loss of habitat, timber and tree growth are considerable when gypsy moth populations are allowed to go untreated.

In Moshannon State Forest District, alone, at least 40 salvage-related timber sales—yielding 16 million board feet–-were the result of gypsy moth outbreaks. Statewide, over 50 million board feet of oak were salvaged on state forest lands between 2006 and 2012 due to gypsy moth damage.

When available, the U.S. Forest Service traditionally provides a 50/50 funding match to states toward annual spraying project costs. If the state funds are not needed for an active suppression program, or not fully utilized, they can be returned for other budgetary uses.

Gypsy moth defoliation in 2014 totaled 213,966 acres, and another 115,104 acres were defoliated by the fall cankerworm. Aerial and ground surveys indicated a total of 431,956 acres of damage by forest pests in 2014.

Before spring 2013, DCNR last sprayed for gypsy moths in 2009, when more than 178,380 acres in 25 counties were targeted across the state. In 2008 a total of 221,221 acres of private, state and federal woodlands were sprayed in 27 counties.

“Private woodland owners and state forest visitors must remember spraying is a suppression effort, a forest management effort to protect trees from moderate to severe defoliation,” said Dr. Donald Eggen, the bureau’s forest health manager. “The gypsy moth will continue its cyclic population with ups and downs, and we cannot eradicate the insect. It’s too well-established and is here to stay.”

Forestry bureau experts identify the gypsy moth as one of the most destructive forest pests in Pennsylvania. Feeding while in the larval—or caterpillar—stage, the insect usually hatches and begins feeding from mid- to late April in southern Pennsylvania, and in early to mid-May in the northern part of the state.

Oak, apple, sweet gum, basswood, birch, poplar and willow trees are affected the most by the gypsy moth. Older larvae also will feed on hemlock, pines, spruces, southern white cedar and other conifers. A tree begins to suffer when 30 percent or more of its leaf surface is lost.

Begun in 1972, forest insect spray programs are a cooperative effort among DCNR's Bureau of Forestry, county governments and the U.S. Department of Agriculture Forest Service's Forest Health Protection Unit.

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

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January 28, 2015

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