TRENTON, N.J. — The New Jersey Department of Agriculture has proposed spraying approximately 4,500 acres of residential and county owned properties in Cape May, Morris, Ocean, Sussex and Warren counties this year to combat the tree-killing gypsy moth caterpillar. The NJDA’s aggressive spray program in 2016 resulted in a more than 75 percent decrease in the number of acres proposed for spraying this year.
“We are pleased to announce that last spring’s sprayings helped 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 spraying 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 2017 Aerial Gypsy Moth Suppression program. Egg mass surveys were conducted from August to December and treatment is proposed for areas of: Upper Township in Cape May County; Jefferson and Rockaway townships in Morris County; Manchester Township in Ocean County; Wanaque Borough and West Milford Township in Passaic County; Stillwater and Vernon townships in Sussex County; and Liberty, Lopatcong 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 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 to combat the tree-killing gypsy moth caterpillar. Both treatments and defoliation are down due to a combination of effective treatments in 2016 and sporadic E. maimaiga (gypsy moth fungus), reducing the populations especially in the northern counties of the state.
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.
Last summer’s defoliation survey included 13,449 acres in 15 counties and 57 municipalities. The majority of the damage was in Sussex (4,841 acres), Warren (4,185 acres), Morris (1,340 acres) and Passaic (759 acres) counties.
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 www.nj.gov/agriculture/divisions/pi/prog/gypsymoth.html. Also, for national gypsy moth material, visit www.na.fs.fed.us/fhp/gm/.