Department of Agriculture | 2018 GYPSY MOTH SPRAY PROGRAM ANNOUNCED skip to main content skip to main navigation

January 3, 2018
PO Box 330
Trenton, New Jersey 08625-0330

Jeff Wolfe
P: (609) 633-2954
C: (609) 433-1785

NJ Dept. of Agriculture Proposes Treating 2,400 acres

(TRENTON) – The New Jersey Department of Agriculture (NJDA) has proposed spraying approximately 2,400 acres of residential and county owned properties in Burlington, Morris, Passaic and Warren counties this year to combat the tree-killing gypsy moth caterpillar. The NJDA’s spray program in 2017 resulted in an almost 50 percent decrease in the number of acres proposed for spraying this year and more than 85 percent reduction from the 2016 proposed spraying program.

“We are pleased to announce that last spring’s applications continue to decrease the gypsy moth caterpillar populations in many areas across the State,” said New Jersey Secretary of Agriculture Douglas H. Fisher.  “We will continue to act by treating the most impacted areas to minimize tree damage and nuisance to homeowners in the coming years.”

The NJDA held an informational session in Trenton today to outline its 2018 Aerial Gypsy Moth Suppression program.  Egg mass surveys were conducted from August to December in 2017.

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 2017, the NJDA’s spray program included 4,500 acres in 11 municipalities in Cape May, Morris, Ocean, Passaic, Sussex and Warren counties to combat the tree-killing gypsy moth caterpillar. Both treatments and defoliation are down due to a combination of effective treatments in 2017 and sporadic E. maimaiga (gypsy moth fungus), reducing the populations especially in the northern counties of the state.

In 2016, the NJDA’s spray program included 20,355 acres in 27 municipalities and one county park system in Cape May, Salem, Hunterdon, Morris, Passaic, Sussex and Warren counties.

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

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   


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