Don’t Give a Free Ride to the Spotted Lanternfly

Spotted lanternfly (SLF), Lycorma delicatula, is an invasive sap-feeding planthopper native to Asia. First identified in Pennsylvania in 2014, it has spread to at least 14 states. While live specimens have not been found in Canada, active populations have been found right across the border in Buffalo, New York, and in Pontiac, Michigan. 

What is it?

Spotted lanternfly is an excellent hitchhiker. Long distance spread to new areas is typically associated with people inadvertently moving overwintering egg masses. Females lay eggs indiscriminately on just about any flat surface. The egg masses are up to 2 cm long (similar in size to those of spongy moth) and covered by a grey, waxy coating that has a putty-like appearance. Over time, the waxy surface becomes dull, making egg masses difficult to detect on some surfaces (Figure 1).  

Figure 1. Spotted lanternfly females and egg masses on a vineyard post
(Photo: Heather Leach, Penn State Extension)

Adults are large (2.5 cm in length) and brightly coloured. Early instar nymphs are black with white spots, while fourth instars are bright red with white and black spots. Nymphs are excellent jumpers. Although adults are not considered strong flyers, they are capable of repeated bouts of flight, resulting in natural spread of several km per year.  There is one generation per year (Figure 2).

Figure 2. SLF has one generation per year in Pennsylvania
(Photo: Colleen Witkowski, Penn State University)

What is the damage?

Spotted lanternfly is a plant stressor. Large numbers can weaken or kill plants. Aggregations (or swarms) of nymphs and adults damage plants directly by feeding on plant sap, and indirectly by excreting large amounts of sugary honeydew that promotes the development of sooty mould and interferes with photosynthesis.

There are over 70 documented hosts in North America, including grapevines, fruit trees, and hardwoods like black walnut, maple, and one of its preferred hosts, the invasive tree-of-heaven. 

To date, reports of economic injury in the US have been confined to commercial vineyards, where swarm feeding has resulted in yield loss, decreased sugar content in harvested grapes, and weakening or death of vines. There is ongoing research on the impacts to tree health in black walnut and maple, both of which are commonly attacked by late instar nymphs and adults in the fall. There have been some dramatic images of SLF swarms on apple, but so far, activity on tree fruit seems to be limited to brief periods in the fall, possibly as the pest searches out more preferred hosts.     

Looking for more information?

If you are interested in finding out more about SLF, the Invasive Species Centre has developed an online course to provide training on the identification, biology, impacts, pathways for spread, and reporting (funded through the Canadian Agricultural Partnership’s AgriRisk Initiatives Program). This self-guided online course is free of cost and can be used to obtain Continuing Education Credits from the Ontario Certified Crop Advisor Association. Click here for more information. 

If you are travelling through infested areas or bringing in supplies from affected regions in the US (see distribution map), be mindful you’re not inadvertently moving eggs or other life stages. Early detection is crucial for effective response and in limiting or slowing the spread. 

If you think you have found SLF, take pictures and report any suspected finds immediately to the Canadian Food Inspection Agency.

Hannah Fraser

Entomologist – Horticulture, OMAFRA