Spotted lanternflies surge again — and this time, they’re heading for Pa. wine country

Philadelphians have largely enjoyed mild lanternfly seasons since the red, black, and polka-dot insect invasion of 2018. But while the bugs may feel like less of a nuisance here, scientists say the threat is far from over — and residents still need to stomp.

On the other side of the state, a resurgence is putting crops at risk and raising concerns about a wider spread. Experts warn that without continued vigilance, including killing lanternflies on sight, the invasive pest could soon bring even more damage across Pennsylvania and beyond.

Spotted lanternflies were first detected in Berks County a decade ago. Julie Urban, an entomologist at Penn State, was among the first scientists called in to assess the damage.

» READ MORE: It’s been a decade since the lanternfly landed in Pennsylvania. Is it as bad as we feared?

Urban and her colleagues noticed that after the first few years of feeding, lanternfly populations seemed to decline, a pattern entomologists expected.

“We can’t really explain it, it’s probably a complex of contributing factors,” Urban said. “But, basically, we think that after multiple years of feeding, they kind of deplete the host plants and move on to other areas. This gives plants time to recover.”

After several years of relative quiet, the lanternflies are back in Berks County.

“It’s not surprising,” Urban said.

» READ MORE: Spotted lanternflies might not be tree killers, according to a Penn State study

Growers there are better prepared this time around, after nearly a decade of support and training from the USDA and research institutions like Penn State and Cornell University.

What’s more concerning, Urban said, is that the lanternfly is rapidly expanding north, now only one county away from Erie — Pennsylvania’s largest producer of grapes, a $50 million industry in the region alone, which is especially vulnerable to lanternfly damage.

That’s especially troubling, Urban said, because Erie’s grapes are primarily used for juice and jelly, far less profitable than wine grapes. That means local growers have fewer resources to fight back.

Currently, the primary control for spotted lanternflies is insecticide, whose standards are reviewed and set by multiple state agencies and federal regulators, and its upkeep costs steep.

“[Erie grape growers] don’t have the profit margins to afford the insecticide required,” Urban said.

While lanternflies haven’t yet made it past Chicago, scientists say it’s only a matter of time before they reach the West Coast — likely within the next decade. That’s why Pennsylvania launched its “Stomp It!” campaign, urging residents to kill any lanternflies they see, especially on cars or cargo that could carry the pest to new regions.

When California growers visited Pennsylvania vineyards to see the damage firsthand, some were stunned.

“One California grower blanched white and said, ‘We’ll go out of business,’” Urban said.

With less pesticide use, limited labor, and widespread reliance on mechanical harvesting — which can suck lanternflies into grape batches — California’s wine industry could face devastating losses if the pest spreads west.

» READ MORE: Spotting and stopping the spotted lanternfly: A guide for homeowners

Scientists “have a lot of irons in the fire” for solutions to lanternfly control, but one is gaining traction: parasitic wasps.

These wasps reproduce by laying egg larvae inside the bodies of a host.

“As someone who’s collected plant hoppers, literally around the world and all over this country, the parasitic wasp is a common natural enemy of plant hoppers across the board,” Urban said. “Even a colleague in Poland who works with plant hopper fossils, you can see fossils that have been parasitized by that type of parasitoid.”

But before America starts unleashing parasitic wasps on lanternfly hordes, rigorous examination must be done to ensure they won’t also go after native crops and wildlife.

In the meantime, most of the state is still under lanternfly quarantine and residents have a “kill on-site” order handed down from the state’s top scientists.

“If you don’t kill it, you’ll carry it,” Urban said. “You’re helping us buy more time to come up with better solutions, and keep these growers in business.”