While on a recent walk around downtown Bethesda, I couldn’t help but stop when I saw about a dozen spotted lanternflies fluttering about on a sidewalk on Wisconsin Avenue.
In our area, spotted lanternflies (Lycorma deliculata) are considered invasive. They are native to eastern Asia and are harmless to humans but cause damage to trees and crops by sucking sap from trunks and stems, according to the Maryland Department of Agriculture. In their adult form, the gray- and red-spotted bugs are characterized as planthoppers that munch on more than 70 species of crops and plants such as grapes, red maple trees and weeping willows. The first confirmed sighting of a spotted lanternfly in Maryland was reported in October 2018.
When I saw the bugs, my first impulse was to stomp on them – following the advice I had learned from invasive species experts in news articles and social media videos – and stomp I did. A handful took short bursts of flight on the sidewalk, escaping the first barrage from my shoe, but mostly I was able to make quick work of the slow-moving insects. As I considered the carnage, my next instinct was curiosity.
How did these bugs get all the way to downtown Bethesda? Are spotted lanternflies the new normal in Montgomery County?
After taking some close-up photos of the bugs and logging my findings into the Maryland Department of Agriculture’s spotted lanternfly sighting registry, I reached out to the Montgomery County Department of Environmental Protection for more information. Later, I spoke with Mary Travaglini, the organic lawn and landscapes manager at the department and the county’s liaison to the National Capital Region Partnership for Regional Invasive Species Management (PRISM), about the invasive bugs.
Travaglini said spotted lanternflies have spread rapidly throughout the Northeast region and were first reported in Pennsylvania in 2014. She said the populations of spotted lanternflies have dropped in the past several years, but the species is “on the move.”
“In the new areas they come into they are showing that they have the ability to reproduce rapidly and have these massive populations,” Travaglini said, noting the bugs were first reported in the county in 2022.
It is possible the insects may have been in the county earlier but in populations likely too small to be spotted, Travaglini said.
This year, the county is starting to see a “big population boom” that has mostly been assisted by humans, according to Travaglini.
“They don’t actually move that far on their own,” she said. “We’ve been transporting them unwittingly on vehicles, on boats, on equipment, on loads of stone, on plant transportation, you name it. If humans are moving it, there’s a chance that spotted lanternfly eggs could be on whatever’s being moved from that area.”
Typically spotted lanternflies lay eggs in masses of about 30 to 50 that are then coated with a gray-beige wax, according to the state’s Department of Agriculture. Spotted lanternflies prefer host trees to deposit their eggs, but flat surfaces such as buildings, trailers, fence posts and vehicles can suffice.
Because these bugs have been hitching rides across states, counties and even into downtown Bethesda, the state has begun regulating the transportation and movement of goods, according to Travaglini.
In January 2022, Montgomery County was added to the Department of Agriculture’s spotted lanternfly quarantine, which “restricts the movement of regulated articles that might contain the spotted lanternfly in any of its life stages,” a news release announcing the quarantine stated. Under the quarantine, businesses, municipalities and government agencies are required to have a specialized permit to transport regulated items such as landscaping or construction waste, packing material, plants and vehicles. In addition, managers, supervisors or employees must be trained and pass an exam to demonstrate an understanding of the pest and quarantine requirements.
On the county level, Travaglini said the government doesn’t have the resources to go from tree to tree individually scraping off eggs or implementing a spotted lanternfly prevention program. But one way the county is taking steps is by educating the public about the threat of invasive species and what residents can do to help.
“If you want to smash them, it’s relatively satisfying when you are having a stressful day,” she said. “If you learn what the egg masses look like, it’s good to get out an old credit card or paint scraper and scrap those off into a plastic bag or another bag that can go straight into the trash.”
Are the lanternflies here to stay?
“That is the question I don’t have a crystal ball for,” Travaglini said when I asked whether the bugs would ever go away. She said it is unclear what the future will hold in terms of population dynamics.
“It’s really difficult to predict and what we do need is more resources towards the control and education around not spreading invasive species and the harm of invasive species,” Travaglini said.
In addition, the spotted lanternflies don’t have enough natural predators feeding on the bugs to make “a big enough dent in the population,” according to Travaglini. Plus, no natural predator could have a high-level impact because of the insects’ sheer volume and population size.
As fall comes and then winter begins, Travaglini said experts are expecting the spotted lanternfly adults and instars, the developmental phases between hatching and becoming adult insects, will die off with the frost and cold.
But come spring, Travaglini noted, the egg masses will start to hatch and begin the spotted lanternfly cycle all over again.
