A few years ago, Steve Fellure would see swarms of spotted lanternflies in the Philadelphia-area when he visited his family. But now, he said, the population of the bugs has waned.
“They're still there but they're not nearly as dense as they were a couple of years ago,” he said. “So they are moving — they're moving west.”
Fellure, the district manager for Davey Tree Service in the South Hills, said there is some anecdotal evidence that the biggest populations of spotted lanternflies may be starting to move on from Pittsburgh where they first took root and ballooned a few years ago, ranging into the suburbs and beyond.
“Now there's a lot, a lot of different efforts to mitigate that before it moves even further west into Ohio, West Virginia,” he said. “It is there now. But the populations are very low there.”
Shannon Powers, a spokesperson for the Pennsylvania Department of Agriculture said that there are fewer reports of spotted lanternflies this year, although Allegheny County has had the most reports.
“While many parts of the state are not seeing as many lanternflies as in past years, the PA Department of Agriculture is still encouraging Pennsylvanians to report them, especially in areas where they haven’t been before,” Powers said in an email.
Fellure said spotted lanternflies have done well in Pittsburgh because there is so much tree of heaven in the city — the plant native to China and Taiwan that happens to be lanternflies’ preferred host. The invasive plants do well in distressed, urban areas, he said.
Last year, Fellure said he and his team of arborists had to fight off a large population of lanternflies in Brentwood Park, close to the city. But this year, he said, those numbers have fallen off.
And while there are more spotted lanternflies in outer suburbs like Upper St. Clair, he said, they haven’t reached the kind of population size he saw last year in Brentwood.
Fellure said he thinks that the local ecosystem has begun limiting their growth, as birds and insects have learned to feed on spotted lanternflies. And he thinks widespread efforts to remove tree of heaven and to target the bugs directly are also having an impact.
“With those things all combined, that's probably — in my opinion — why we're seeing population density not being so high this year,” he said. “And it's also a nuisance pest. So their populations do tend to go in ebbs and flows. So maybe we're on the decline.”
Keeping populations in check
Spotted lanternflies rarely kill a tree directly, Fellure said. Instead, they weaken the tree by eating the nutrients from the vascular system in its leaves and stems. In addition, their excrement is dark and prone to mold, which makes it difficult for the trees to photosynthesize, turning the leaves yellow.
Many flowering ornamental trees are also at risk, Fellure said, including elms, walnuts, oaks, crabapples and dogwoods. In particular, Fellure said he’s seen an increase in eastern redbud trees that he thinks have been weakened by spotted lanternflies dying from disease and insects.
“In my opinion, you get that stress from spotted lanternfly feeding on it,” he said. “It reduces overall vigor and disease and pest resistance. And then we have those that move in and kind of finish the plant off.”
In a dense park or forest area, he said, the trees may be strong enough to withstand the onslaught, as they can draw from a deeper reservoir of nutrients in the soil. And they can potentially benefit from other creatures in the area that keep the lanternflies at bay. But he said sometimes those very same trees will struggle in a suburban yard where they don’t have the same kind of protection that a native ecosystem provides.
Fellure said he recommends individual homeowners add double-sided tape to the trees in the spring and early summer, before the spotted lanternflies can fly. They’ll often get stuck on the tape when they are still nymphs. He also recommends adding additional nutrients to a tree that may be under attack to help them fight off the stress of the insects.
Efforts to squash the bugs in your neighborhood can help limit the population growth, Fellure said.
“Don't think that squashing one lanternfly bug isn't helping because it is. They do have to reproduce. They do have to replenish their population every year,” he said. “So the more that we can do to reduce that, the better off we're going to be.”
