By: Madison Sturba, Training and Outreach Intern

Spotted lanternfly (SLF; Lycorma delicatula) is lurking dangerously close to the Canadian border. These 1-inch planthoppers may seem harmless given their small size and colourful butterfly-like appearance, but they can destroy native and economically important plants in the areas they invade.

SLF adults can be found congregating in massive groups on their host trees. Built-up honeydew on tree trunks and branches can promote sooty mold growth. Photo: Richard Gardner, Bugwood.org

Though spotted lanternfly has yet to be found in Canada, they have been confirmed in neighbouring U.S. States, including New York, Pennsylvania, and Ohio. Experts are especially concerned about these insects hitchhiking their way from New York into Ontario’s Niagara Peninsula, which is Canada’s largest wine region. These ravenous insects devour the sap from over 70 different plant species with a particular preference for grapevines and fruit trees. If SLF were to make their way into this region, they could significantly damage Ontario’s multibillion-dollar wine (viticulture), tree-fruit, and maple industries.

How do these insects damage plants? Spotted lanternflies suck out sap from the vascular systems of plants by feeding on phloem (sugar conducting) tissues. In doing so, they remove plant resources and threaten fruit quality. Spotted lanternflies also excrete sugary honeydew, which not only rains down from individuals high in the tree canopy, but also builds up on the bark and base of trees. This sticky honeydew can cause further damage by promoting fungal growth and attracting other insects, such as wasps, ants, and bees.

SLF egg masses laid on a park bench. The mud-like mass in the center is a fresh egg mass that has been covered in a protective coating. The masses on the far right and left are old, hatched egg masses. Photo: Emelie Swackhamer, Penn State University, Bugwood.org.

Spotted lanternflies can spread quickly over large distances by laying inconspicuous egg masses on the hard surfaces of cars, trucks, and trains. These durable egg masses are brown or grey in colour and are easily mistaken for smears of dried mud. It’s also common for adults to cling onto moving vehicles, as two dead adult spotted lanternflies were found by the Canadian Food Inspection Agency (CFIA) on commercial trucks travelling from Pennsylvania to Québec in September 2020. With travel restrictions lifting along the Canadian and U.S. border, concerns of SLF arriving in Canada are on the rise.

You can help prevent the arrival of SLF by learning where its preferred tree hosts (such as the tree-of-heaven) are planted in your community and watching these areas for any SLF activity. Since invasive egg masses can be found on outdoor hard surfaces, monitor areas such as rock and wood piles, BBQs, siding and door frames. If you think you’ve spotted SLF, report the sighting by visiting https://www.invasivespeciescentre.ca/report-a-sighting/ or https://www.eddmaps.org/.

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