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Photo of a gypsy moth caterpillar - Click to enlarge
For Immediate Release: August 6, 2012
Contact: Lynne Richmond
(609) 633-2954

(TRENTON) – The annual New Jersey Department of Agriculture statewide gypsy moth aerial defoliation survey showed 1,068 acres of trees in 21 municipalities in 10 counties received moderate to heavy damage this year from the leaf-munching invasive pests -- the lowest recorded defoliation since the Department’s Gypsy Moth Suppression Program began in 1970.

“Fighting the gypsy moth problem in a multitude of ways and partnering with the State Department of Environmental Protection, counties, municipalities and the military bases has led to the lowest populations of the damaging insect in the 42-year history of the program,” said New Jersey Secretary of Agriculture Douglas H. Fisher. “But this success can be short-lived if we do not continue intense surveillance, as well as treatment, when necessary.”

The defoliation survey was conducted in July.  Tree damage was found in Atlantic, Burlington, Cape May, Gloucester, Hunterdon, Monmouth, Ocean, Salem, Sussex and Warren counties.  The most damage seen was in Mullica Township in Atlantic County, which had 344 acres of mostly moderate defoliation.  For more details from the survey, go to

Gypsy moth caterpillars lay their eggs on trees and emerge in May and early June.  This year, no spray program was needed due to low populations of the bugs.

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.  Egg mass surveys will be conducted this fall to determine if any areas qualify.

Gypsy moth populations can be cyclical.  Tree damage from the insects reached a high of 339,240 in 2008, but through the combination of the Department’s aggressive spray program, an army of beneficial insects and weather that supported a fungus that impacts gypsy moths, populations have collapsed over the last four years.

Vigilance is necessary for continued success of the program.  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