Gypsy Moth Caterpillar Damage Relatively Light, but Ocean County Hit Hardest

Newly released survey data from the Department of Agriculture shows that Ocean County bore the brunt of tree damage from gypsy moth caterpillars this year, and even though it was a light year overall for the insects’ populations statewide, officials say the bugs aren’t on their way out.

The gypsy moth is an invasive insect native to Europe and Asia. First introduced to the U.S. in the mid 1800s, it has spread across much of the country, causing extensive damage to native hardwood forests as its caterpillars, which have few predators here, devour the leaves of oaks and other deciduous trees.

Ocean County municipalities were affected most by gypsy moth caterpillars’ destructive munching this spring, according to the DOA, with 228 acres of trees affected. In Barnegat, 10 acres of woods saw defoliation – significantly less than neighboring Stafford, which had 94 affected acres.

Defoliation was more severe in Berkeley Township, where 70 acres were heavily affected by the insects. Other areas that have been hard hit in the past, including Manchester and Toms River, had no visible damage this year.

Check out the full report from the DOA here. 

Joe Zoltowski, chief of the DOA’s Bureau of Plant Pests and Disease Control, said gypsy moth populations rise and fall in cycles, and are affected by the state’s spraying program as well as weather patterns. Despite the fact that there was very little spraying this year – only a few acreage blocks in Camden County – the number of defoliated acres in the state declined from last year.

But that doesn’t mean municipalities should stop worrying about the insects, he said. 

“Overall, in the grand scheme of things the populations are pretty low,” said Zoltowski, “but they could start building next year. We’re kind of in the same boat we were in in 1999.”

That year, there were few gypsy moths and little damage, and in the year that followed, the state did very little spraying. Aided by dry weather, gypsy moth populations exploded in following years. As recently as a few years ago, he said, the Department of Agriculture was overseeing the spraying of tens of thousands of acres of trees.

Now the population is down again, he said, but “these bugs aren’t going to go away.”

But the state’s control program is designed to respond to the fluctuating insect population, and target areas most in need. In the spring, the DOA conducts a statewide aerial survey from Cape May all the way up to Sussex County, said Zoltowski. Areas that show defoliation are then mapped out, and his department notifies affected municipalities.

Those towns can then request that the DOA do an egg mass survey later in the year to examine the extent of the gypsy moth population, and can request areas be sprayed.

They key, he said, is to keep the program going, even when populations dip. 

“When we start to see those numbers getting out of hand, at least we’re not starting from ground zero,” he said.