NJDA Proposes Treating County for Gypsy Moth Caterpillars

EWING – The New Jersey Department of Agriculture (NJDA) has proposed treating approximately 5,000 acres of residential and county owned properties in Burlington and Cape May counties this year to combat the tree-killing gypsy moth caterpillar. 
“The treatment program has proved very effective during the last several years and has significantly decreased the gypsy moth caterpillar populations across the state,” New Jersey Secretary of Agriculture Douglas Fisher stated.  “By treating these areas now, we can prevent this insect’s spread and keep the populations at a minimal level for the years to come.”
The NJDA held an informational session in Ewing today to outline its 2022 Aerial Gypsy Moth Suppression program. Egg mass surveys were conducted from August to December in 2021.
A combined seven municipalities in Burlington County and Cape May County are recommended for treatment. Participation in the program is voluntary. If the towns agree, treatments will take place in May and June. To qualify for the 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. 
Less than 200 acres were recommended for treatment in 2021, also in Burlington and Cape May counties. The Burlington County municipality opted to not do treatment last year and 50 acres were treated in Cape May County. No areas of the state were recommended for treatment in 2019 and 2020.
In 2018, the NJDA’s program included approximately 4,000 acres of residential and county owned properties in Burlington, Morris, Passaic, and Warren counties. That was about an 80 percent reduction from the 2017 program. The defoliation decreased due to a combination of effective treatments and sporadic E. maimaiga (gypsy moth fungus), reducing the populations.
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.