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Photo of a gypsy moth caterpillar - Click to enlarge
NJ Dept. of Agriculture Proposes Spraying of More Than 20,000 acres

For Immediate Release: January 6, 2016
Contact: Lynne Richmond
(609) 633-2954

(TRENTON) - The New Jersey Department of Agriculture has proposed spraying 20,354 acres in 27 municipalities and one county park system in Cape May, Salem, Hunterdon, Morris, Passaic, Sussex and Warren counties this year to combat the tree-killing gypsy moth caterpillar.

"Last spring we saw an increase in gypsy moth caterpillar populations in certain areas that now qualify for the Department's spray program," said New Jersey Secretary of Agriculture Douglas H. Fisher.  "By acting swiftly and spraying the most impacted areas, we hope to minimize tree damage and nuisance to homeowners in the coming years."

The Department of Agriculture held an informational session in Trenton today to outline its 2016 Aerial Gypsy Moth Suppression program.  Egg mass surveys were conducted from August to December and treatment is proposed for areas of: Middle and Upper Townships in Cape May County; Upper Pittsgrove Township in Salem County; Holland, Bethlehem and Alexandria Townships in Hunterdon County; Boonton, Jefferson, Montville, Washington, and Rockaway Townships, Kinnelon Borough and areas of three county parks in Morris County - Mahlon Dickerson, Silas Condict and Pyramid Mountain Park; Bloomingdale and Ringwood boroughs, West Milford Township in Passaic County; Hampton, Sparta, Stillwater, Vernon, Wantage and Frankford Townships in Sussex County; and Blairstown, Frelinghuysen, Liberty, Hardwick, Knowlton and White Townships in Warren County.

Participation in the program is voluntary.  If the towns agree, spraying would take place in May and June.  To qualify for the spray program, a residential or recreational forest must have an average of more than 500 egg masses per acre and be at least 50 acres in size.  A single egg mass contains up to 1,000 eggs.

In addition to the New Jersey Department of Agriculture (NJDA) spray program, the New Jersey Department of Environmental Protection (DEP) is planning to spray 880 acres on 13 state properties in Morris, Passaic, Sussex and Warren counties.  These include high use areas such as campgrounds, picnic and swimming areas, historic sites, along the Appalachian Trail and adjacent to some NJDA spray blocks.

In 2015, the NJDA's spray program included 288 acres in Morris County -- two residential areas and two county parks, Mahlon Dickerson in Jefferson Township and in Silas Condict Park in Kinnelon Borough.

The NJDA and DEP use Bacillus thuringiensis (B.t.) to combat gypsy moth.  It is a biological insecticide that kills the gypsy moth caterpillar when ingested. 

In last summer's defoliation survey, 290,696 acres of trees in 175 municipalities in 20 counties were damaged by gypsy moth caterpillars.  Most of the tree damage was in the seven northernmost counties in the state, with the highest concentrations in Sussex, with 112,149 acres; Passaic with 61,386 acres; and Morris with 60,699.  The hardest hit towns were West Milford in Passaic County with 40,632 acres of trees defoliated and Jefferson Township in Morris County with 22,562 acres. 

Two to three consecutive years of significant defoliation (defined as 75 percent or more) can kill an otherwise healthy tree. However, any gypsy moth defoliation can make trees more susceptible to other damage that can lead to the death of the tree.   Oak trees are the preferred host for gypsy moths, but the caterpillars can be found feeding on almost any tree in the vicinity.

For more information on New Jersey's gypsy moth suppression program, visit:   Also, for national gypsy moth material, visit