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

The species likes feeding on grapes, and it’s present in New York State. That has scientists and locals growers worried about cross-border travel
By Justin Chandler - Published on Aug 24, 2021
The spotted lanternfly feeds on more than 70 types of plants. (AP Photo/Matt Rourke, File)



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. 

“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. 

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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.

left: bugs on a tree trunk; right: a woman with long hair and glasses
Left: Lanternflies on a tree trunk. Right: Mandy Ehnes, program-development coordinator at the Invasive Species Centre. (Courtesy of Mandy Ehnes)

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.

What could the impact be in Ontario?

Given that the spotted lanternfly can easily evade detection, it seems unlikely to stay stateside. “I don’t mean to be alarmist when I say this, but it’s likely not a matter of if — it’s a matter of when,” Ehnes says. That worries Ontario’s farmers, particularly those who grow grapes.

drawing showing the lifecycle of a lantern fly
(Courtesy of the Invasive Species Centre)

Fraser, who conducted a presentation about the lanternfly with Ehnes at the 2021 Ontario Invasive Species Forum, says that it doesn’t usually kill the plants it feeds on, which include fruit trees, black walnut, maples, and oaks. Its preferred host, the tree of heaven, is one exception. Grapes are another. “They love grapes,” Ehnes says. “Once those populations get established, they are bad.” A single vineyard, she notes, could host 10,000 lanternflies: “Wineries especially get hit hard. They can be, for lack of a better word, nuked. They’ll kill everything.” Growers with infested vines must either spray pesticides many more times a year or give up, she says. 

According to the Grape Growers of Ontario, “Ontario-grown grapes for Ontario-grown wines contribute over $4 billion annually to the Ontario economy, and employ over 18,000 people.” That’s why the industry is already taking action. Debbie Zimmerman, the organization’s CEO, says preventative measures are the focus right now, as invasive species “can devastate a vineyard.” Working with Ontario’s agriculture ministry and the Canadian Food Inspection Agency, Zimmerman says, the GGO hosts webinars about lanternflies — and, as part of an industry-funded, government-led research project, 65 lanternfly traps have been placed on trees of heaven in tourist and transportation corridors in southern Ontario. To date, no lanternflies have been caught.

Zimmerman notes that this is another challenge for grape growers, who, along with wineries, have been hit hard by the pandemic: “They’re resilient bunch; there’s no doubt about it. But there are so many things coming at them.” 

many bugs on a tree trunk
Spotted lanternflies gather on a tree in Kutztown, Pennsylvania, in 2019. (AP Photo/Matt Rourke) 

What can the public do?

So far, officials say, raising public awareness is the best way to prevent a major lanternfly infestation. South of the border, there’s already a lot of outreach in affected states, Ehnes says. (At one Pennsylvania university, the pest’s presence spurred the creation of lanternfly-squishing Instagram accounts.) The Invasive Species Centre — founded through a 2011 partnership between the federal government and the province — is working with Ontario’s agriculture ministry and the CFIA on outreach and has produced fact sheets. “We try to encourage people and empower them to know about the pest and to be aware that their actions and behaviour matter,” says Christine Villegas, a senior specialist with the CFIA’s plant-protection division. She says that checking one’s belongings before leaving an infested area, knowing what the pest looks like, and reporting any sightings are critical. According to Ehnes, reporting the presence of trees of heaven, which is also considered invasive, is another way to get ahead of the pest.

What can government do?

Once an invasive species is reported to the CFIA, officers verify the sighting and survey the area to determine next steps, Villegas says — and if lanternflies were to be detected, steps could include implementing control measures, such as the closing of certain areas to the public: “It’s really restricting that movement that helps us to minimize the impact, minimize the spread, and contain the pest in [one] area.”

Villegas notes that, while certain biological and chemical controls used to kill lanternflies in the U.S. show promise, those products have not yet been approved in Canada. 

It’s not practical for border-service workers to search all incoming vehicles, Villegas says, but the CFIA communicates with the Canada Border Services Agency to educate workers about the species — and discussions with multiple government and industry bodies about developing prevention measures are ongoing. 

What should you do if you see a spotted lanternfly?

a brochure outlining the risks posed by the spotted lantern fly
The Invasive Species Centre works to raise awareness of the risk lanternflies pose. (Courtesy of the Invasive Species Centre)

Ontarians who spot a tree of heaven or lanternflies can report them to the Early Detection and Distribution Mapping System. Across Canada, people can use the iNaturalist app to report sightings, or contact the CFIA directly

“Prevention is the best bang for your buck,” Ehnes says. “It is highly likely that we will get spotted lanternfly in Canada. We need to be able to spot it and find it and eradicate it immediately.”

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