‘This is a scary one’: Experts brace for the arrival of the invasive spotted lanternfly

Mandy Ehnes recalls standing beneath a tree just off a recreational trail in Allentown, Pennsylvania. Above her, something was dripping down — a lot of something. “It felt like it was raining,” Ehnes says. Only it wasn’t. The tree was infested with spotted lanternflies. The spotted lanternfly feeds on more than 70 types of plants. (AP Photo/Matt Rourke, File)

“You could see them all over,” she says. There were younger insects up in the canopy and adults swarming the trunk. “They feed on phloem tissue, which is the sugary tissue inside the tree,” she explains. “They’re constantly excreting this sugary sticky substance called honeydew.” That sticky bug poop is what was raining down on Ehnes and getting into her clothes and hair. “This actually fosters mold growth, which is a really stinky thing,” she says. “It’s this awful cascade.”

Ehnes, program-development coordinator at Sault Ste. Marie’s Invasive Species Centre, subjected herself to the stickiness while on a work trip because she wanted to see first-hand what a spotted-lanternfly infestation was like. A particularly disruptive species, it’s known for swarming plants and making messes. “This is a scary one,” Ehnes says. 

The big bright-red fly, which is native to China, India, and Vietnam, was first spotted in the United States in 2014, in Berks County, Pennsylvania. Since then, it has established populations throughout the eastern U.S., despite control efforts. Of special concern to experts in Ontario: the species particularly enjoys feeding on grapes, and it’s present in New York State, just a border away from the agriculturally significant Niagara Region, where much of the province’s wine is produced. And, while there are currently no established lanternfly populations in Canada, that could change as cross-border travel resumes, increasing the avenues for entry into the country. “There are concerns now, especially with people moving across the border,” Ehnes says.

What makes this species such a successful invader?

The spotted lanternfly is thought to have arrived in the U.S. on a stone shipment at some point between 2012 and 2014. “They feed on over 70 types of plants, and although they lay their eggs in the vicinity they’re growing up in, they’ll lay their eggs on anything,” Ehnes says. Although they tend to prefer flat surfaces such as cars, patio furniture, and landscaping stones, she adds, she has come across pictures showing eggs on a hat. 

Hannah Fraser, an entomologist with the Ontario Ministry of Agriculture, Food and Rural Affairs, says the lanternfly has “all the right stuff”: the species’ eggs can survive winter, it has no natural predators in North America, it’s mobile, and females produce a lot of eggs. Once they do, they cover them with a sort of putty that sticks them in place. “When that dries, it makes it really hard to see on certain surfaces,” she says.

As eggs attached to objects move along transportation corridors, spotted-lanternfly populations spread. Ehnes and Fraser say making people aware of what egg masses look like is one way they hope to prevent the insect’s spread, but both acknowledge this is easier said than done. Fraser calls the egg masses “cryptic” because they may just look like dirt — something a border-crossing driver could easily miss on their vehicle.