Their eggs started hatching in the spring and since then they’ve been spotted by the thousands, wreaking havoc on New Jersey’s trees and shrubs.

I’m talking about those pests, the spotted lanternflies.

These bugs have the potential to kill trees that they are feeding on but George Hamilton, extension specialist in pest management at Rutgers University-New Brunswick, said he has not really seen that happen with mature trees in New Jersey. He has. however, seen young saplings get attacked and die from spotted lanternflies.

There have been incidences of death of grapevines in vineyards in Pennsylvania related to feeding due to spotted lanternflies, but here in New Jersey, that has not been seen yet, Hamilton said.

However, repeated infestations have the potential to weaken and kill plants and trees over time in the Garden State.

Invasion of the Lanternflies
AP Photo

How do spotted lanternflies kill trees and shrubs in New Jersey?

Spotted lanternflies feed on trees and plant sap and while they do that, they remove fluids from the trees.

Since the fluid is low in terms of nutrients that they need, the bugs have to feed on and remove large amounts of material than what they can actually process.

They have to excrete a lot of fluid as they are feeding. That fluid is a sugary substance known as honeydew. It gets on surfaces, on lower leaves on trees, and plants below trees, and that sugary substance is attracted to what is called sooty mold.

This is a black mold that grows and accumulates. When that happens, plant materials will turn black. This interferes with photosynthesis which can hurt the understory plants below the trees on which the spotted lanternflies are feeding.

Spotted lanternfly egg masses (New Jersey Department of Agriculture)
Spotted lanternfly egg masses (New Jersey Department of Agriculture)

Are spotted lanternflies done invading and swarming New Jersey?

Not quite, Hamilton said.

The female spotted lanternflies will be laying their eggs during October. So, that means the invasive pests will be around until Mother Nature delivers a good, hard frost. That will kill the adults, he said.

If the frost comes early, there will be probably less egg laying than there would be if the frost comes later in October or early November, Hamilton said.

Each egg mass has at least 30 eggs in it, he added. You can’t miss them on trees. The fuzzy mass is light gray in color. The mass then darkens and turns into a brown or dark gray color.

New Jerseyans are encouraged to stomp and squish adults as they see them.

Spotted Lanternfly (NJ Dept. of Agriculture)
Spotted Lanternfly (NJ Dept. of Agriculture)

What should we do if we come across a spotted lanternfly egg mass on a tree?

Hamilton said don’t do anything yet. At least not until the first frost.

“If you’re going to do something about egg masses that you can find on the trees and shrubs on your property, you might as well wait until it colds enough to kill all the adults. That way you won’t have to do it multiple times,” Hamilton said.

But when it is time to get rid of the egg masses, simply scrape them off the tree. Residents have until mid to late April to scrape the egg masses off trees before the eggs begin to hatch, he said.

Circle traps have been used to get rid of adult lanternflies. They do attract a large number of spotted lanternflies.

“We have a graduate student in our department. She has caught, I think, 6,000 of them with those traps in her research,” Hamilton said.

The traps can be put up on trees on a residential property. It’s simple. He said the spotted lanternflies crawl in, and they can’t get back out. Dump the trap when it’s full and put it back up to catch more.

So, until the first hard frost of the season arrives, keep stomping, squishing, squashing, and trampling the adults as you come across them.

Jen Ursillo is a reporter and anchor for New Jersey 101.5. You can reach her at

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