The tiny bug with black and gray spots crawled up the side of a Center City office building unnoticed by everyone — except Josh Palley, who recognized it as a spotted lanternfly, a dreaded recent plague in Pennsylvania farming country.

"I was leaving work and spotted it on the sidewalk directly outside of the Graham building at 15th and Ranstead Streets," said Palley, a senior director at EPAM global, who read about the lanternfly's spread when he came across a leaflet distributed at the Philadelphia Folk Festival.

"We were all asked to kill any that we see because each one you kill prevents 100 eggs in the next generation," Palley said.

But he was surprised to see one across from City Hall. He squished it.

"It's a shame they're so terrible," Palley said. "They really are beautiful."

The loathed spotted lanternfly, an invasive pest from Asia, is invading Philadelphia.

Lycorma delicatula was first discovered in the United States in Berks County in 2014. It's a major pest for agriculture as it can damage fruit trees, ornamental trees, woody trees, vegetables, herbs, and vines — though it does not bite or sting humans.

The spotted lanternfly feeds on plants by piercing them to get at sap. In the process, they excrete liquids that cause wounds on the plants and facilitate mold growth.

The pest has spread so fast in Pennsylvania that the federal government pitched in $17.5 million this year to help the state fight it. The pest is now in 13 counties. Most of Southeastern Pennsylvania is under quarantine.

Alain Joinville, a spokesperson for the Philadelphia Parks & Recreation Department, confirmed the insect has been found at the Fairmount Park Horticulture Center, Wissahickon Valley Park near Northwestern Avenue and East Falls. A single spotted lanternfly was seen along Valley Green Drive early last week in the Wissahickon. The Wissahickon Environmental Center reported that the bugs appeared in Roxborough last fall but were quickly destroyed.

Locations where the spotted lanternfly has been detected in Wissahickon Valley Park and other locations. From an unofficial map on Facebook.
SPOTTED LANTERNFLY WATCH FACEBOOK PAGE
Locations where the spotted lanternfly has been detected in Wissahickon Valley Park and other locations. From an unofficial map on Facebook.

The insect is attracted to Philadelphia for a key reason: It loves the tree of heaven, or Ailanthus altissima, also an invasive species, that has been in Philadelphia since the 1800s. It prospers in places other trees don't: sidewalk cracks, building foundations, and along roadsides.

Humans have had a big role in the spread of the lanternfly, which hitches rides on cars and trucks traveling from rural areas to suburban communities, and now the city. It lays eggs on vehicles, especially in wheel wells.

Spotted lanternfly on outdoor furniture in Chester County.
Jamie Caughey
Spotted lanternfly on outdoor furniture in Chester County.

Jamie Caughey, who lives with her family in suburban Chester Springs, said she's seen entire trees infested with the critters in the parking lot of a Target store in West Pottsgrove and covering pumps at nearby gas stations.

"It was shocking to see that many," Caughey said. "They were all over the ground, all over the pumps, just flying around because this tree of heaven goes up and down the routes."

Spotted lanternfly infest a tree at a shopping center parking lot in West Pottsgrove, Pa. in late August.
Jamie Caughey
Spotted lanternfly infest a tree at a shopping center parking lot in West Pottsgrove, Pa. in late August.

Dana Dentice, urban forestry program manager for the Pennsylvania Horticultural Society, said the insect begins laying its eggs in the fall and continues into winter. Residents who spot eggs are urged to scrape them into bags filled with rubbing alcohol or hand sanitizer to kill them.

Eggs may also be found on patio furniture, trailers and other hard surfaces. They've been known to attack birch, poplar, willow, and a lot of other tree species common to the city.

“They’re going to be really challenging to contain,” Dentice said.