Arlington’s swarms of spotted lanternflies will finally go away over the winter, but residents should expect to see even more next year, experts say.
The invasive insects, which have appeared en masse in Arlington this year after sporadic sightings for the last few years, will die with the first frost, Alonso Abugattas, natural resources program manager for Arlington County, told ARLnow. This typically takes place around Oct. 25.
However, the pests’ egg masses can survive the winter and will hatch again in the spring.
“Populations of spotted lanternflies will likely continue to trend upwards for another year or two,” Abugattas said.
Still, the population will stabilize eventually. Predators like birds, mantises, wasps and assassin bugs have started to eat the lanternflies, and some people have started to remove the insects’ favorite host plant, the invasive tree of heaven.
Researchers have been studying Verticillium nonalfalfae (a fungus) for 20+ years as a potential biological control for the invasive Tree-of-Heaven (Ailanthus altissima). Several ISC affiliates ran the fungus through efficacy tests in Virginia ⬇️https://t.co/d5T1GzIEPR pic.twitter.com/VwgSOGeSKm
— Invasive Species Collaborative @ VT (@ISWGvt) March 20, 2025
“One thing preventing more predators from eating lanternflies is that lanternflies become unpalatable when they feed on invasive Tree-of-Heaven trees and absorb toxins from the tree,” Abugattas said. “As we reduce the number of Tree-of-Heaven locally, the lanternflies will become more edible to local predators.”
Arlington County has begun proactively removing trees of heaven from parks and replacing them with native trees. Abugattas encouraged residents to help out on private land, too.
“People should actively consider removing Tree-of-Heaven on their property as it is the preferred host of lanternflies as well as an invasive species that negatively impacts our local, native ecosystems,” he said.
Spotted lanternflies don’t bite or sting people or pets, but they do cause stress on native plants including maples and native grapes. “The most notable harm” comes to crops such as grapes in Virginia’s vineyards, Abugattas said.
Abugattas recommended against using insecticides to kill spotted lanternflies, since those chemicals can also harm beneficial insects. Crushing the bugs can also be helpful, though it’s not the most effective approach.
“Squashing lanternflies will not significantly impact their population, but if you are able to correctly identify them, it is beneficial to squash them,” he said. “Removing invasive Tree-of-Heaven trees is the most recommended action available to reduce lanternfly populations.”
