Arlington residents should expect a couple more seasons of spotted lanternfly infestations before the invasive species’ numbers start to decline.
Birds, bats and perhaps even a specialized type of wasp will likely help to thin the ranks of the lanternflies, which have been damaging native trees and plants since they became a common sight in Arlington around summer 2024.
“Slowly, the animals will learn to manage them,” said Alonso Abugattas, natural-resources manager for the Arlington County government, during an Aug. 21 online forum sponsored by Virginia Cooperative Extension.
That turning point is expected to arrive in 2028 or 2029, based on observations in Pennsylvania, the first state to see a major lanternfly influx.
While the insects’ numbers will be reduced, they are here to stay, Abugattas said:
“You can’t put the genie back in the bottle. They’ll become just another pest — they won’t cause the great harm they did in the past, [but] they’re never going to go away.”
His advice to the public remains the same — kill lanternflies when you encounter them.
“Do the best you can for the next couple of years,” Abugattas said. “One less lanternfly is one less likely to breed.”
While lanternflies are highly prevalent around Arlington right now, their presence varies between different locations.
“It’s happening all over our neighborhoods,” said Leslie Fillmore, the agriculture and natural-resources agent for Virginia Cooperative Extension’s Arlington-Alexandria office. “Some people have seen a whole lot, while others are seeing only a few here and there.”
Participants in the hour-long forum confirmed that assessment.
Betty Belanus, a North Arlington resident, is among those witnessing significant impacts.
“We had a lot of nymphs in our grapevines, and now they are becoming adults,” she said in an online chat during the forum. “They pretty much devastated our grapes, so we will not get many to eat, if at all.”
Alexandria resident Eileen Powell said the infestations appear to be very site-specific this year.
“I live in Del Ray and haven’t seen any locally, but I have seen them in friends’ gardens in North Arlington and Northwest D.C.,” she said.
Brian Costello, another forum participant, said trying to contain the spread of lanternfly can be discouraging to those who value their natural surroundings.
“This battle can seem somewhat futile,” he said.
The good news, Abugattas said, is that at least in residential areas, the impacts to date have been relatively minimal.
“For us, it’s mostly a nuisance,” he said. “If it’s a healthy plant, [the insects are] not likely to kill them.”
Also good news: Lanternflies are not dangerous to people or pets. They do not bite or sting.
Much of the forum focused on ways to eliminate the insects, which are most attracted to walnut, maple and fruit trees. Homemade sprays with bases like dish soap, white vinegar, rubbing alcohol and soybean oil are effective, while scraping eggs off trees and disposing of them also will help slow the spread.
The discussion also concerned what to do about the tree of heaven, the lanternflies’ preferred host plant.
The trees were imported to the U.S. beginning in the 1780s from China by way of Europe. Initially prized for their ornamental value, the trees fell out of favor by the late 1800s because of their negative impacts on the overall ecosystem.
The tree of heaven grows quickly and, when mature, can spread up to 300,000 seeds per year. Few native species eat the plant, and roots will start sprouting new trees even if the existing tree is cut down, said Jennifer Soles, a natural-resource specialist for the county government.
The trees also release toxins that can inhibit the growth of neighboring plants, according to Virginia Cooperative Extension.
Arlington officials currently are culling tree of heaven on county owned property, and residents can report those they find on public property. About 100 currently are awaiting action.
“Don’t expect an immediate turnaround — we will get to them as we can,” Soles said.
The same situation is true in Alexandria, said Katrina Napora, the city’s natural-resource manager.
“We do have a limited amount of resources and a lot of tree of heaven,” she said.
Neither locality has the power to compel people to remove the tree of heaven from private property, although Soles suggested those who see them on private lots could bring the situation to the property owner’s attention.
There are ways to treat tree of heaven rather than removing them, although that option likely also would require professional intervention, Soles said. The trees are notoriously difficult to kill.
One possible containment strategy includes the use of parasitic wasps, also native to China, whose females feed on spotted lanternfly nymphs.
Studies are occurring to weigh the pros and cons of introducing the wasps as a tool for control.
“We’ll see,” Abugattas said.
The forum was one of a series of educational programs sponsored by the local office of Cooperative Extension, a joint program of Virginia Tech and Virginia State University supported by the Arlington and Alexandria governments.
It coordinates efforts of Master Gardeners of Northern Virginia, including an education series with programs open to the public.
A video recording of the event will be posted in coming weeks as part of the Master Gardeners’ “virtual classroom.”
The local Cooperative Extension office offers a “help desk” for people with questions, including those related to spotted lanternfly and tree of heaven. Available weekdays from 9 a.m. to noon, experts can be reached by phone or online.
