Residents across the Philadelphia region have been stomping, squishing, and otherwise snuffing out the spotted lanternfly, an invasive pest that has taken over backyards and parks and threatens to kill off trees.

Now, it is time for the next step.

Find and kill the eggs.

The distinctive insect with spotted brown and red wings is a plant hopper native to China, India, and Vietnam. It was first discovered in the United States in 2014 in Berks County, likely brought in as eggs on a crate of stones imported from China.

Since then, the bug has spread across the region in what U.S. scientists say is the worst invasion since the gypsy moth started defoliating millions of acres of forests and killing countless trees in a process that started more than a century ago.

Reaction to control the spotted lanternfly has been swift.

Researchers at Pennsylvania State and Cornell Universities are studying an EPA-approved biopesticide spray already on the market that they hope will contain the spread of the spotted lanternfly.

And there have been countless educational programs aimed at enlisting the public to help slaughter the bugs before they wipe out black walnut and maple trees and grapevines. The bug’s favorite snack is the Tree of Heaven, once popular in garden landscapes but also an invasive species that has spread about the region.

While the spotted lanternfly is easy to recognize, its eggs are not so obvious.

“It takes a little practice before you recognize them,” said Richard Roush, dean of the college of agricultural sciences at Penn State.

Just before she lays her eggs, the female will get swollen and develop an orangish streak, he said.

“They don’t fly so well because they are quite heavy,” Roush said. It also makes them easier to catch and kill, he added.

The insect tends to lay eggs in areas protected from wind and harsh winters. That could be the underside of a tree limb or on any surface that is sheltered. The egg stage is the most vulnerable of the spotted lanternfly life cycle because they are stationary for months, he said.

The female secretes a white, foamy substance on the eggs to protect the mass. The size of the mass can vary, but it’s typically about an inch long by 3/4 of an inch wide. On surfaces that females especially like, there can be multiple egg masses. When they dry they look like light grayish splotches of mud, or even mortar. Each mass holds 30 to 50 eggs, he said.

Spotted lanternfly egg masses on the base of a Tree of Heaven in the Norristown Farm Park taken in April 2019.
Emelie Swackhamer
Spotted lanternfly egg masses on the base of a Tree of Heaven in the Norristown Farm Park taken in April 2019.

Penn State researchers have found that about 80% of the eggs they see are laid high up in tall trees, Roush said. They hope to soon come up with a way to reach those areas with pesticides.

Right now, the regional hot spots for spotted lanternfly activity are in the Conshohocken area, lower Montgomery County, Chester County near West Chester, and south of Philadelphia along the I-95 corridor, said Emelie Swackhamer, a horticulture extension educator at Penn State Extension in Montgomery County.

“They are going to continue to lay eggs until we get the first killing frost,” she said. Look for the egg casings especially if you are moving anything off of your property. Cars and tires should be inspected to make sure the insect is not hitching a ride, she said.

Swackhamer cautions against using any home remedies to eliminate the bugs or eggs. The internet is filled with suggestions such as using dish soap, vinegar, salt, boric acid, vegetable oil, garlic, or chili/cayenne peppers, which may end up harming plants, pets, humans, and beneficial bugs. And, there are no data to suggest these remedies will work on the spotted lanternfly, she said.

Once you have identified a spotted lanternfly egg mass, killing its contents is straightforward, she said.

Add rubbing alcohol or hand sanitizer to the inside of a zipper-sealed plastic bag. Then use a plastic card — like a credit card — or a putty or butter knife to scrape the egg mass into the bag. Make sure you scrape the area completely. Seal up the bag and make sure the alcohol mixture comes in contact with the eggs. Want to go alcohol-free? Just collect the eggs in a bucket and squish them.

Mission accomplished.

By the way, Swackhamer notes, don’t blame the spotted lanternfly for those dead ash trees around the region. Those are from the emerald ash borer, another invasive pest, she said.

Visit the Penn State Department of Agriculture website on the spotted lanternfly for more tips and updates on how to control the pest, she said.

The eggs can be found everywhere including:

  • Basketball backboards
  • Recreational vehicles
  • Tarps
  • Plant containers
  • Firewood
  • Propane or oil tanks
  • Trash cans
  • Shutters, doors, and windows
  • Outdoor furniture
  • Barbecue grills
  • Fencing
  • Trees, shrubs, and plants
  • Playhouses
  • Kiddie pools
  • Sandboxes
  • Trampolines

Pennsylvania residents who encounter the spotted lanternfly should report its location to the Penn State hotline at 1-888-422-3359 or online at extension.psu.edu/have-you-seen-a-spotted-lanternfly. In New Jersey, email at SLF-plantindustry@ag.nj.gov or call 1-833-BAD-BUG-0 (1-833-233-2840) with details and contact information. Early detection is vital for the protection of businesses and agriculture.