This summer, New York residents have been urged to look out for a new invasive insect, the spotted lanternfly, and squish it on sight.
Illinois residents are being asked for something different: Look for the insect — pale purplish with flashes of orange on its hind wings — and take a picture so experts can confirm its identity. Email the photo to [email protected], where experts from a consortium of Illinois agencies will examine it.
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“In Illinois, we do not have a positive confirmation,” said Tricia Bethke, forest pest outreach coordinator at The Morton Arboretum in Lisle.
If the insect is not here, it’s likely on the way, she said. Spotted lanternflies can lay their eggs on any vertical surface, including the sides of cars, trucks and train cars, so the eggs are easily transported along highways and railroad lines. They have already been found in 11 states including Indiana, Ohio, Iowa, Pennsylvania and New York.
Spotted lanternfly, a voracious sap-sucking insect from Asia that isn’t really a fly, is known to feed on more than 70 species of trees and other plants. It’s a big problem for farmers who grow fruits such as apples, peaches and cherries or the hops used in beer-making, as well as wineries that grow grapes.
It also feeds on trees including maple, oak, walnut, sycamore, pine and willow. “It’s not likely to kill a tree on its own, but if the tree is already weakened by drought stress or disease, an infestation by spotted lanternflies could be the knockout punch,” Bethke said.
The spotted lanternfly does not represent the same kind of devastating threat to trees as the emerald ash borer, which has wiped out hundreds of millions of ash trees across the United States. However, it is one of a number of invasive insect pests, including the spongy moth and Asian longhorned beetle, that collectively menace U.S. trees. Learn more at the Facebook page of Illinois Invasive Species Awareness and Management, facebook.com/IllinoisISAM.
Despite the name, the spotted lanternfly is a planthopper, rather than a fly. Nor is it a moth, although the adult looks a bit like one. At rest, it shows pale outer wings with black spots; when it opens its wings, one set is splotched with orange.
In eastern United States, large concentrations of spotted lanternfly adults have been a maddening late-summer annoyance to campers and picnickers. “It could be a real problem in places like our forest preserves,” Bethke said.
Kim Kalosky, a resource specialist with the Forest Preserves of Cook County, worries that the arrival of this invasive species will impact quality of life in other ways, too.
“It’s going to be a major burden to outdoor recreation,” she told the Post-Tribune earlier this week, emphasizing the impact on native walnut and oak trees. “Our natural areas host so many millions of visitors. We have hundreds of miles of trails, hundreds of picnic areas, and if we have the type of infestation that’s happening out east in some counties, people are not going to want to be outside.
Chicago and its suburbs could offer a lush life for spotted lanternflies because they have so many of the pests’ absolute favorite food, tree of heaven (Ailanthus altissima). An invasive plant from eastern Asia that sprouts and spreads easily and grows in difficult conditions, tree of heaven is common in vacant lots, railroad rights of way and other neglected places, as well as many yards.
According to the 2020 Chicago Region Tree Census conducted by the Arboretum, 5% of all trees in the city are tree of heaven. But it’s everywhere. “We have tree of heaven in every county in Illinois, even the most rural areas,” she said.
Once the insects are established in a tree of heaven, their eggs could easily hitchhike to other trees and fruit crops. The adults can fly a short distance, but the pests are most likely to spread when unnoticed egg masses on vehicles, firewood, boats or other objects are moved by people.
Because tree of heaven is a prime target for the spotted lanternfly, Bethke has helped train and organize citizen scientists to locate and report the locations of the trees through a smartphone app. “Knowing where tree of heaven is helps us know where spotted lanternfly is likely to be,” she said. Learn more at EDDMaps.org.
Homeowners and gardeners can also help by keeping a sharp eye out for both the adult insects and their egg masses, and sending in photos for positive identification. Adults are active from late summer through fall. According to the U.S. Department of Agriculture, they are easiest to spot at dusk or at night as they crawl up and down tree trunks. The eggs are laid in late summer and may be found through the winter on vertical surfaces such as tree bark, stone, metal, sheds, the sides of cars or home siding. An egg mass is a light-colored splotch with a waxy gray coating.
“We’ve learned a lot about these insects from the experience of other states,” Bethke said. “If the public can help us detect them early, Illinois can limit the damage.”
The Plant Clinic can help homeowners identify tree of heaven. If the trees are removed, homeowners can avoid providing a cozy home for spotted lanternflies.
For tree and plant advice, contact the Plant Clinic at The Morton Arboretum (630-719-2424, mortonarb.org/plant-clinic, or [email protected]
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). Beth Botts is a staff writer at the Arboretum.