New research suggests invasive spotted lanternfly may be able to survive Canadian winters

Research out of the Great Lakes Forestry Centre in Sault Ste. Marie, Ont., is raising new concerns about an invasive insect that has been steadily moving closer to the Canadian border.

“Unfortunately, what we have found is that the spotted lanternfly, particularly their eggs, are actually able to withstand really cold temperatures,” said Amanda Roe, a research scientist with Natural Resources Canada based at the forestry centre.

Recent studies have found that spotted lanternfly eggs can survive temperatures up to -25 C, suggesting winter may not be enough to prevent the destructive pest from establishing populations in parts of Canada, she said.

"Winter itself isn't going to be a barrier, particularly in the areas of Canada where their impact might be greatest," Roe said.

The destructive spotted lanternfly is a sap-sucking insect native to Asia that feeds using straw-like mouthparts to pierce the surface of trees and plants, allowing it to suck out the sap.

It was first detected in the United States in 2014. Since then, it has spread rapidly across the eastern U.S. and established populations in at least 19 states, including Michigan and New York, and communities along the shores of Lake Erie, according to Roe.

The insect feeds on more than 100 plant species, said Olivier Morin, a plant health survey biologist for the Canadian Food Inspection Agency.

"The main impact that is expected will be on grape productions. It doesn't mean that it will not impact other productions or other plants, but the main impact will be grapes," he said.

In infested areas of the United States, spotted lanternflies have caused significant problems for vineyards and other agricultural operations.

Large numbers of the insect feeding on plants can reduce yields and weaken crops. They also produce large amounts of a sugary waste known as honeydew, which coats surfaces and encourages mould growth.

“They like to eat the things that we also like,” Roe said. “They’re more of a fun killer than, say, a tree killer. But those are really important commodities in many parts of Canada.”

The insect also feeds on maple trees, something that has caught the attention of Canada’s maple syrup industry.

The Ontario Maple Syrup Association has been monitoring the spotted lanternfly for the past three years as researchers work to better understand the risks it may pose.

“We don’t know enough about their impact on maple to understand what its potential impact might be on, say, maple syrup production,” she said.

"It's that uncertainty that is troubling because we don't actually have an answer. And part of that is because the populations of spotted lanternfly are only really recently spreading into those areas where maple syrup production is an important activity."

While current studies provide insight into the insect’s cold tolerance, Roe explained that invasive species can continue adapting to new environments over time.

“We haven’t entirely figured out what that northern boundary is,” she said. “As long as there’s food, the opportunity is there.”

Plant health biologist Olivier Morin explained human activity remains one of the biggest factors in the spread of the insect.

“The spotted lanternfly is a super good hitchhiker,” he said.

Unlike many insects that rely on natural dispersal, spotted lanternflies frequently travel long distances by attaching themselves to vehicles, cargo, shipping containers and other outdoor equipment.

Females can lay egg masses on almost any hard surface, including trailers, picnic tables, campers and boats.

The Canadian Food Inspection Agency has intercepted spotted lanternflies on cargo shipments, vessels and vehicles arriving from the United States, some of them alive, according to Morin.

“We haven’t found any established populations yet,” he said. “But we see that the pressure is there for sure.”

Anyone who encounters a spotted lanternfly should take a photograph, collect the insect if possible and place it in a sealed container before reporting it to the Canadian Food Inspection Agency, Morin said.

“We expect spotted lanternfly to arrive and spread into Canada,” Morin said. “We will do our best to slow that spread and delay as much as possible the impacts it’s going to have.”