James Wolf and his young son bent over some tiny hopping dots on a patch of green in Wyman Park in North Baltimore. “Yep, here they are,” he said, pointing to insects resembling polka-dotted peppercorns.
The pint-size pests are hard to see now, but they will be impossible to avoid in a couple months. Experts expect the population of spotted lanternflies, an invasive insect originally from China, to boom in Baltimore and the surrounding suburbs this summer. The insects will grow and molt throughout the summer, revealing larger and showier bodies with each transformation. When fully grown, they will throng in large masses among their favorite trees, secreting a shimmering mist of excrement.
Spotted lanternflies don’t sting or bite and are not poisonous, but they can weaken young plants, attract hornets, spur the growth of unsightly mold, and cause significant damage to hops and grape vines. Plus the sheer volume of mature winged insects that will be swarming throughout the region this summer will have residents reaching for their swatters.
“It’s like a less-fun version of the cicadas,” said Megan Carr, an urban forester with the Baltimore City Department of Recreation and Parks. Like other experts, Carr recommends a simple, safe and time-honored method of controlling the pests: squishing them.
Spotted lanternflies hitched a ride to Berks County, Pennsylvania about a decade ago in a shipping container of rocks. Despite efforts to control the movement of the bugs out of that state, they have slowly fanned out along the Eastern Seaboard and are also heading west. A database compiled by Cornell University’s New York State Integrated Pest Management program shows that the most intrepid insects have traveled as far as Vermont, South Carolina and Indiana.
Locally, Harford and Cecil counties experienced an explosion of spotted lanternflies over the past couple of years. Late last summer, the bugs covered the trunks of trees so thickly in Harford’s Palmer State Park that the bark appeared to be undulating.
In March, the Maryland Department of Agriculture expanded the spotted lanternfly quarantine zone to include all but six of the state’s 22 counties. The counties in which the insects have not yet been seen are what Kenton Sumpter, an agriculture department entomologist who is leading the state’s response to the pest, described as “the tips of Maryland”— Garrett in the far west, and Charles, St. Mary’s, Dorchester, Somerset and Worcester to the south and east.
Early signs point to a baby boom of spotted lanternflies in the state’s central regions, Sumpter said. “Baltimore City is getting bad really fast and Baltimore County is following closely behind,” he said. “Any place that caught lanternflies last year, I expect it will be worse this year.”
The mature insects are about the size of a thumbnail and sport bright red inner wings cloaked by translucent gray outer wings. They flitted into the Baltimore region late last summer to find love and lay eggs. Their offspring began hatching last month, latching onto the stems and vines of young plants that provide the sustenance to power them through several cycles of growth.
While young spotted lanternflies will eat just about anything, the adults are pickier eaters. One of their favorite foods is another invasive species — the ailanthus, better known as tree of heaven. These trees, which also originally hail from China, edge out other trees in forests and are ubiquitous throughout the city, sprouting from parks, vacant lots and even vacant buildings.
The bugs that Wolf, president of The Friends of Stony Run, found in Wyman Park last week were meandering across vegetation under some trees of heaven. Carr, the city’s urban forester, had led the Stony Run group members through the park a few days earlier to look for the bugs. While spotted lanternflies don’t permanently harm most plants, they can damage young trees, such as the native oaks, pawpaws and elms that Wolf and the members of the group have planted.
“We’ve been planting a lot of young trees in the name of habitat restoration and they’re at risk,” said Wolf.
Residents have been noticing the creatures throughout the region in recent weeks. Carol Ott saw about a dozen of them munching on the rose bushes in her Waverly garden about a week ago. She killed them with a squirt of insecticidal soap, but a few days later noticed another clambering about her coleopsis.
Teresa Duggan of Hampden saw several nymphs on her picnic table last week, which she squished, but not before snapping a picture for Instagram.
Anne Gonnella also noticed a few spotted lanternflies scurrying across a picnic table at her Ellicott City home last week. “The unfortunate thing is they’re really cute,” she said.
James Reusing was not surprised to see spotted lanternfly nymphs in his Glen Arm yard since he fended off many of the adults last year. “We had a ton of them out here last fall,” said Reusing. “I’d just sit out here with a Red Ryder BB gun and blast them. With the red wings, it was a very colorful explosion.”
Reusing said he inspected trees on his property for egg cases over the winter, but didn’t spot any. The egg cases are a light grayish tan, resembling a smear of chewed up gum, and tend to blend into bark.
But while the bugs are a nuisance, they don’t pose serious harm for people, pets or most plants. “We want to emphasize to folks that this insect can certainly cause some damage, but it’s not catastrophic,” said Carr. She recommended that those concerned about the pests remove trees of heaven from their property and plant native trees instead.
Spotted lanternflies do attract trouble as they mature and begin to emit a sticky waste product, euphemistically termed “honeydew.” Yellow jackets, bald-faced hornets and European hornets enjoy slurping up honeydew and are often buzzing about areas with large concentrations of spotted lanternflies, said Sumpter, of the state department of agriculture.
Honeydew also fosters the growth of sooty mold, a knobby black fungus that looks like something out of a post-apocalyptic Dr. Seuss book. The mold eventually coats branches and leaves in areas where the bugs congregate.
But the most serious risk posed by spotted lanternflies is to grape vines. The little lushes suck so much sap from grape vines that they can kill plants or make them produce fewer or less appealing grapes, experts said.
Sumpter said his team has been traveling to vineyards to spread the word. Most vineyard owners will likely need to use pesticides to keep the bugs in check, he said, since the squish ‘em method is not effective on a large scale. “They’re going to need to spray because there are just so many bugs,” he said.
Vineyard owners are bracing themselves for the onslaught.
“So far only the anxiety has arrived,” said Bert Basignani, co-owner of the northern Baltimore County winery that bears his name. Basignani said Sumpter’s team had found and removed egg masses from several trees around the vineyard and neighboring properties. While he had yet to see any young spotted lanternflies, Basignani said he was prepared to use insecticides if necessary to quell the population in June and July.
At Frederick County’s Black Ankle Vineyards, co-owner Sarah O’Herron said she saw a few mature bugs late last summer, but has yet to find nymphs this year. O’Herron said she had been removing trees of heaven from her property. State agriculture workers had cleared away egg masses at Blank Ankle too, she said.
While O’Herron was also prepared to use insecticides to control the pests, she said she hoped that the bugs would not be as bad as anticipated. “We have lived through a number of invasive pests: stink bugs, lady beetles, spongy moths,” she said. “They go through a cycle where they’re impervious to everything, then they catch a fungus or a virus or a predator discovers them.”
There is some anecdotal evidence that backs up O’Herron’s theory, Sumpter said. Residents have reported the population of spotted lanternflies appears to be decreasing in Cecil County, where they had been most concentrated in the past, he said. Wheel bugs, praying mantises and some spiders have started eating the adults. Natural population controls may help to keep the bugs in check after a few seasons of exponential growth, he said.
In the meantime, Sumpter and Carr advised against using large amounts of strong pesticides to kill the bugs or sticky traps that can also snare birds. We’ll need to get used to living with spotted lanternflies, much as we have grown accustomed to stink bugs, another invasive insect from Asia.
Sumpter said, “They’re just always going to be here.”